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Biomedical subjects

J Cartwright

Publications and source records attributed to J Cartwright.

At least 37 records · Page 2Linked to original sources
PubMed1995

Long-term histopathologic changes in canine aneurysms embolized with Guglielmi detachable coils.

PURPOSE: To evaluate the long-term histologic changes, including those in the ultrastructure of the neoendothelium, occurring in experimental canine aneurysms obliterated with Guglielmi detachable coils. METHODS: Ten experimental aneurysms were surgically created in mongrel dogs using side-to-side jugular carotid fistulas that were subsequently ligated to form blind pouch venous aneurysms dependent on the carotid circulation. The aneurysms were obliterated with Guglielmi detachable coils, and the animals were kept in observation. Six months after the endovascular obliteration of the aneurysms, repeat carotid arteriography was performed to assess for potential recanalization of the aneurysms. The animals were then killed and submitted for autopsy. The carotid artery and the embolized aneurysm were resected and studied with light and electron microscopy. RESULTS: Both completely obliterated and recanalized aneurysms were excluded from the parent circulation by an endothelialized layer of connective tissue. The fundus of the aneurysm was completely obliterated by heavy reactive fibrous tissue surrounding the coils with very minimal, if any, inflammatory reaction. The neointima is composed of three well-identifiable layers, the most superficial of which is formed of new endothelial cells positioned next to each other in a cobblestone fashion over a basal membrane. CONCLUSION: In the absence of histologic data in human aneurysms obliterated with Guglielmi detachable coils, several observations made in our experimental study help in the understanding of the long-term results expected from this endovascular technique.

Aneurysm↗
PubMed1994

Thymic nurse cells are sites of thymocyte apoptosis.

Thymic stromal cells play important roles in thymocyte differentiation and selection. Thymic nurse cells (TNC) are thymic epithelial stromal cells that envelop two to 200 CD4+CD8+ thymocytes (TNC-T). The mechanism by which TNC complexes form and their role in thymocyte development are unknown. TNC have been implicated as specialized microenvironments for proliferation, positive selection, negative selection, and apoptosis. Using TCR-gamma junctional sequence analysis of thymocytes within individual TNC, eight of ten TNC analyzed were polyclonal, and two showed evidence of oligoclonality. TCR-alpha beta expression was not detectable on most TNC-T and SCID mice, which do not express TCRs because of a defect in TCR gene rearrangement, had normal numbers of thymocyte-bearing TNC. Thus, TCR expression is not necessary for TNC formation. Treatment of mice with Abs to CD3 epsilon, which induces apoptosis in immature thymocytes, resulted in an eightfold increase in TNC per thymus with 95.5% apoptotic TNC-T. These results suggest that a function of TNC is the clearance of nonfunctional, nonselected, apoptotic thymocytes.

Animals↗
PubMed1994

Effect of fibrous glass on rat pleural mesothelium. Histopathologic observations.

Female Fisher 344 rats (n = 25) were inoculated intrapleurally with a single 20-mg dose of (JM-100) fibrous glass. The mean length (2.2 microns) and width (0.15 microns) of the fibrous glass particles was within respirable range. Following inoculation, the rats were killed at timed intervals ranging from 2 to 430 d from inoculation. The pleural histopathologic changes were independently observed by a panel of three pathologists blinded to the time elapsed from inoculation. Fibrous adhesions, nodular lesions, and grossly evident tumor were noted in 15, 2, and 1 rat, respectively. In 1 rat there were combined adhesive and nodular changes, and in 6 there were no grossly detectable abnormalities. Chronic inflammation, fibrosis, and foreign body reaction were found in 9, 18, and 10 rats, respectively. Mesothelial hyperplasia and dysplasia were observed in 16 and 9 rats, respectively. Of 16 rats with the severest degree of hyperplasia and dysplasia, 3 developed malignant mesothelioma. This study suggests that a spectrum of rat pleural mesothelial histopathologic changes occurs before development of mesothelioma. The association of severe dysplasia in 3 rats with fully developed mesothelioma suggests that there may be a gradual progression from mesothelial hyperplasia or dysplasia to mesothelioma. Multivariate analysis further suggests that gross pleural nodular lesions and dysplasia may be significantly associated with the development of mesothelioma in this experimental model.

Animals↗
PubMed1993

Active site-blocked factor Xa prevents thrombus formation in the coronary vasculature in parallel with inhibition of extravascular coagulation in a canine thrombosis model.

Factor Xa is a central procoagulant enzyme, linking the intrinsic and extrinsic activation mechanisms to the final common pathway of coagulation. To assess its contribution to pathologic thrombosis, studies were performed in a canine coronary thrombosis model. Thrombus formation was initiated by the application of electric current via a needle electrode placed in the lumen of the left circumflex coronary artery. When 50% occlusion of the vessel developed, the current was stopped and animals received an intravenous bolus of either saline, bovine glutamyl-glycinyl-arginyl-factor Xa (Xai), a competitive inhibitor of factor Xa assembly into the prothrombinase complex, Factor X, or heparin. Animals infused with saline or factor X (300 micrograms/kg) developed total occlusion of the vessel due to a fibrin/platelet thrombus in 70 +/- 11 minutes (36 of 36 animals) and 74 +/- 13 minutes (8 of 8 animals), respectively. In contrast, infusion of Xai prevented thrombus formation completely at a dose of 300 micrograms/kg (8 of 8 animals). As the dose of Xai was decreased, its antithrombotic effect was diminished, with a patency rate of only 2 of 6 animals at a dose of 90 micrograms/kg. Xai at 300 micrograms/kg prevented the accumulation of 125I-fibrinogen/fibrin at the site of the coronary thrombus by approximately 63% and decreased deposition of 111In-labeled platelets by approximately 57%. Hemostatic parameters of animals infused with Xai demonstrated prolongation of the PT and dose-dependent increased extravascular bleeding tendency. These data indicate that factor Xa has a comparably important role in thrombus formation and extravascular hemostasis, and contrast with previous results in this same animal model in which IXai selectively prevented clotting in the coronary vasculature.

Amino Acid Sequence↗
PubMed1993

Amiodarone pulmonary toxicity: a multidisciplinary review of current status.

Amiodarone, a benzofuran derivative, has proven useful in the control of serious cardiac arrhythmias. We reviewed the English language medical literature to characterize clinical, radiographic, scintigraphic, pathologic, diagnostic, and prognostic data concerning amiodarone pulmonary toxicity. Our review showed that features consistent with amiodarone pulmonary toxicity include exertional dyspnea, fever, and high sedimentation rates, usually in patients taking larger maintenance doses. Positive findings on gallium scan, foamy alveolar macrophages on lung biopsy or bronchoalveolar lavage, and resolution of abnormal chest roentgenogram upon withdrawal of amiodarone and/or institution of corticosteroid therapy support a diagnosis of amiodarone pulmonary toxicity. Conversely, maintenance doses of 400 mg or less daily, normal lung diffusing capacity and bronchoalveolar lavage or lung biopsy specimens without foamy alveolar macrophages are features that make amiodarone pulmonary toxicity unlikely. Amiodarone pulmonary toxicity should be considered in any patient who has new or clinical worsening of respiratory symptoms and/or abnormalities on chest roentgenogram. Congestive heart failure is often present in these patients and must be excluded before a diagnosis of amiodarone pulmonary toxicity can be considered. Amiodarone pulmonary toxicity also needs to be distinguished from pulmonary infection. Therefore, amiodarone pulmonary toxicity remains a clinical diagnosis relying upon a composite of clinical, radiographic, and histopathologic findings.

Amiodarone↗
PubMed1992

Calcium oxalate in breast lesions biopsied for calcification detected in screening mammography: incidence and clinical significance.

Two types of calcification have been reported in breast tissue: one appears as dark-blue deposits in routine histologic tissue sections and has been found to be composed mostly of calcium phosphate (CaP); the other is colorless and represents calcium oxalate (CaOx). CaP has been well characterized, but little is known about CaOx. The presence of CaOx was evaluated in 91 breast lesions (71 retrospective and 20 prospective cases) biopsied for the presence of calcification in screening mammography. CaOx was found in 36 cases (39%). CaOx is usually not clearly visible in routine histologic sections. CaOx is found as refractile, strongly birefringent crystals with characteristic morphology. CaOx was present only within benign lesions which frequently showed apocrine metaplasia. However, the breast tissue away from the areas with CaOx displayed a morphologic spectrum roughly similar to that in cases with CaP only. CaOx was clinically significant, i.e., actually represented the mammographic calcification, for which the biopsy was performed in 12% (11/91) of all cases studied and in 31% (11/36) of cases in which CaOx was found. In the cases where CaOx was not considered clinically significant, it was either not radiographically visible or, if visible, did not definitely represent the mammographic calcification for which the biopsy was performed. Since CaOx in breast biopsies is often clinically significant, and since CaOx is not clearly visible in routine sections, examination under polarized light is suggested for all breast biopsies removed for mammographic calcification, particularly when CaP deposits corresponding to the mammographic calcification are not apparent.

Adult↗
PubMed1991

Aicardi syndrome. A clinicopathologic case report including electron microscopic observations.

Aicardi syndrome is characterized by infantile spasms, agenesis of the corpus callosum, severe mental retardation, and a characteristic chorioretinopathy with lacunar defects. The authors report on a 2-year-old girl with congenital hydrocephaly who was found unresponsive by the baby-sitter and died shortly thereafter. At autopsy, the histopathologic findings, which were confined to the brain and eyes, were found highly characteristic of AIC. The main abnormalities included agenesis of the corpus callosum, micropolygyria, bilateral papillomas of choroid plexi, bilateral microphthalmia, bilateral hypoplasia of the optic nerves, bilateral colobomas of the juxtapapillaris choroid and optic disc, bilateral total retinal detachment with dysplastic rosettes and chorioretinal lacunae with focal thinning, and atrophy of the retinal pigment epithelium and choroid. A detailed histopathologic study of the ocular findings and the brain anomalies is presented. The results of scanning electron microscopy of the chorioretinal lacunae demonstrated peculiar papillary proliferations of the retinal pigment epithelium in both eyes.

Agenesis of Corpus Callosum↗
PubMed1991

Pseudofungi in a lymph node. A case report with energy dispersive X-ray elemental analysis.

A case of pseudofungi in axillary lymph nodes is presented. They resembled septate hyphae and were stained with a periodic acid-Schiff stain. Gomori methenamine silver stain failed to stain them. Because of morphologic similarity to true septate fungi and positive staining with periodic acid-Schiff stain, these structures can be misinterpreted as septate hyphae forming true fungal organisms. Further studies, some of which included energy-dispersive x-ray elemental analysis and special stains, revealed that they were composed of iron, phosphorus, and calcium. The relationship of these pseudofungi to previously published cases and clues that enable one to make a correct diagnosis are described.

Aged↗
PubMed1991

Pre- and postnatal growth retardation--severe mental retardation--acral limb deficiencies with poorly keratinized nails. Another example of a distinct syndrome of inherited intrauterine dwarfism?

In this report, we further delineate an autosomal recessive syndrome with prenatal growth retardation, severe postnatal growth failure, profound mental and motor retardation, characteristic face and acral limb deficiencies with poorly keratinized nails and hypoplastic distal phalanges.

Child Development↗
PubMed1990

Renal amyloidosis characterized by abnormally thick fibrils.

A renal biopsy of a 57-year-old man with nephrotic syndrome revealed marked glomerular deposition of Congo red-positive, bire-fringent material characteristic for amyloid. Ultrastructurally, however, this material is composed of nonbranching, haphazardly arranged fibrils of approximately three times the thickness of typical amyloid fibrils. To our knowledge, there has been no report of such a finding, and this unique case enlarges the morphologic spectrum of renal fibrillosis.

Amyloidosis↗
PubMed1989

Cytomorphometry of large cell carcinoma of the lung.

A computerized morphometry system was used to evaluate criteria for the cytologic diagnosis of large cell carcinoma (LCC) and poorly differentiated adenocarcinoma of the lung. There were 143 cells measured in six cases of LCC (five sputums and one bronchial washing) and 61 cells in four cases of adenocarcinoma (all sputum samples). Cellular and nuclear areas were significantly larger in adenocarcinoma whereas nucleolar area was greater in LCC, producing a higher nucleolar/nuclear area ratio in LCC. Cellular and nuclear form factors were smaller in LCC while the minor axis was longer in adenocarcinoma, resulting in a smaller axial ratio in adenocarcinoma. These data indicate that adenocarcinoma cells are larger and have a more rounded shape and less nucleolar material, as compared to the smaller, more ellipsoid and convoluted cells of LCC, which have more nucleolar area. A logistic regression identified cellular area, nucleolar/nuclear area ratio and cellular and nuclear form factors as significant contributors to the discrimination of LCC from adenocarcinoma, with a positive predictive value of 92%. Morphometry may therefore be helpful in the differential cytologic diagnosis of adenocarcinoma and LCC.

Adenocarcinoma↗
PubMed1989

Segmental mediolytic arteritis. A clinicopathologic and ultrastructural study of two cases.

We describe the histopathologic and ultrastructural changes in two cases of segmental mediolytic arteritis (SMA) and summarize the clinical and pathologic findings in previous reports. SMA is initiated by the transformation of the arterial smooth-muscle cytoplasmic contents into a maze of dilated vacuoles containing edema-like fluid. With vacuolar rupture, the smooth-muscle cells are disrupted and the mediolytic process completed. Mediolysis is accompanied by fibrin deposition and hemorrhages at the adventitio-medial junction and within the media. Inflammation is inconstant and limited to the periadventitial tissues. Transmural mediolysis leads to the formation of arterial wall gaps--defects in the vascular wall bridged by a serofibrinous layer. The serosal and intramural arteries and arterioles of the jejunum and the epicardial coronary arteries were the targets of SMA in this report. SMA occurs in two clinical settings: (a) in abdominal muscular arteries and arterioles of predominantly elderly patients presenting either with ischemic bowel disease or shock, and (b) in the coronary arteries of neonates in conditions associated with severe hypoxemia. We conclude that SMA is the result of an inappropriate vasospastic response expressed in a splanchnic vascular bed undergoing vasoconstriction as a response to shock or severe hypoxemia.

Aged↗
PubMed1989

Nonmelanized macromelanosomes in a cellular blue nevus. Light and electron microscopic observations.

We noted nonmelanized and partially melanized macromelanosomes in a cellular blue nevus and studied their light microscopic and ultrastructural features. Numerous intracytoplasmic eosinophilic inclusions were found in the lesion; individual cells contained up to nine, although most cells demonstrated two or three. The "macromelanosomelike" inclusions ranged in size from 1 to 15 microns. Most of them were partially melanized, and some were nonmelanized. These globules were periodic acid-Schiff positive and diastase resistant, with a centrally melanized core, best seen with the Fontana-Masson technique. S100 protein stained positively the cytoplasm of some nevus cells but not the inclusions. Electron microscopy confirmed the centrifugal melanization of these structures and their targetlike morphologic characteristics. Nine other cellular blue nevi from our files failed to show similar intracytoplasmic inclusions.

Female↗
PubMed1988

Lead arthritis and lead poisoning following bullet wounds: a clinicopathologic, ultrastructural, and microanalytic study of two cases.

Bullet wounds causing lead synovitis in the wrist and knee are reported in two patients, one of whom also developed clinical plumbism. Very high lead levels in the synovial fluid are believed to be responsible for toxicity changes that occurred in the synovium and bone. Ultrastructurally, these alterations included the formation of nuclear lead inclusions, dilation, and degranulation of the rough endoplasmic reticulum and deposition of crystalline precipitates in the matrix of the mitochondria in macrophages, osteoclasts, and synoviocytes, as well as the development of cytoplasmic lead inclusions in osteoclasts. Energy-dispersive x-ray elemental analysis (EDXEA) indicated that the nuclear inclusions contained only lead, whereas precipitates within the mitochondria and elsewhere in the cytoplasm were composed of complexes containing lead, calcium, and phosphorus. Similarly constituted extracellular complexes were incorporated into newly formed trabecular bone laid down as a physiologic response to the bullet lodged within the wrist bones. This bone subsequently exhibited defects in bone resorption, which were characterized by depressed osteoclastic function and a unique lesion termed incomplete osteocytic osteolysis. The genesis of this latter lesion is uncertain. The sequestration of the partially degraded bone fragments containing lead complexes into the marrow and eventually into the joint spaces and synovium permitted the recycling of bone lead, and this may have played an important role in inducing clinical plumbism in one of the patients in this study.

Adult↗
PubMed1988

Pseudoparasitic Liesegang structures in perirenal hemorrhagic cysts.

Periodic structures with equally spaced radial striations identified as Liesegang-like rings were seen in two male patients' hemorrhagic perirenal cysts. The patients, one 48 and the other 60 years old, had acute right-flank pain and anemia; both had nephrectomy. The rings, initially believed to represent parasites (Dioctophyma renale), were from 8 to 500 micron in diameter and had uniform, pink-tan, radially striated double walls. Multiple small rings within a larger ring predominated in one case. Morphologically, the rings differed from D. renale when compared with specimens from animals infected naturally or experimentally with the giant kidney worm. Histochemical and immunoperoxidase tests for iron, calcium, mucopolysaccharides, amyloid, keratin, and hemoglobin had negative results. Energy-dispersive x-ray elemental analysis demonstrated no detectable elements; ultrastructurally, however, the rings displayed a fine fibrillary composition with a concentric and radial pattern. These rings are believed to be an end product of a phenomenon resembling or are, in fact, the Liesegang phenomenon. Because these Liesegang-like structures may be mistaken for parasites on fine-needle aspiration or surgical specimens of hemorrhagic areas, pathologists should be aware of them.

Cysts↗