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Biomedical subjects

J Bjornsson

Publications and source records attributed to J Bjornsson.

At least 19 recordsLinked to original sources
PubMed2001

Gestational attenuation of Lyme arthritis is mediated by progesterone and IL-4.

Infection of different strains of laboratory mice with the agent of Lyme disease, Borrelia burgdorferi, results in arthritis, the severity of which has been correlated with the dominance of Th1 cytokines. In this study, we demonstrate that changes in B. burgdorferi-specific immunologic responses associated with pregnancy can alter the outcome of Lyme arthritis in mice. Whereas nonpregnant female C3H mice consistently developed severe Lyme arthritis, pregnant mice had a marked reduction in arthritis severity that was associated with a slight reduction in IFN-gamma and markedly increased levels of IL-4 production by B. burgdorferi-specific T cells. Similar reductions in arthritis severity and patterns of cytokine production were observed in nonpregnant, progesterone-implanted mice. Ab neutralization of IL-4 in progesterone-implanted mice resulted in severe arthritis. Our results are consistent with the known shift toward Th2 cytokine expression at the maternal-fetal interface, and are the first to show a pregnancy-related therapeutic effect in an infectious model.

Animals↗
PubMed2000

Fatal pulmonary toxicity related to the administration of granulocyte colony-stimulating factor in amyloidosis: a report and review of growth factor-induced pulmonary toxicity.

We report on a 59-year-old man with renal amyloidosis who died after three doses of granulocyte colony-stimulating factor were administered. Noncardiac pulmonary edema was precipitated by the growth factor. Autopsy revealed amyloid in the lung not visible by plain chest radiograph. Patients with amyloidosis who are candidates for stem cell transplantation and are mobilized with growth factors must be monitored for unexpected pulmonary toxicity. We review the in vitro experimental evidence as well as the clinical data on the pulmonary toxicity of growth factors.

Amyloidosis↗
PubMed1999

The role of parvovirus B19 in the pathogenesis of giant cell arteritis: a preliminary evaluation.

OBJECTIVE: To determine whether parvovirus B19 DNA is more likely to be present in the temporal arteries of patients with giant cell arteritis (GCA) than in the temporal arteries of control subjects. METHODS: We prospectively examined temporal artery biopsy (TAB) tissue from 50 consecutive patients presenting for TAB for the presence of B19 DNA using the polymerase chain reaction (PCR). Clinical and demographic information was obtained from the patients' medical records. A separate PCR analysis of 30 original tissue specimens was conducted at the Centers for Disease Control and Prevention (CDC) using primers directed toward another target sequence in the nonstructural coding area of B19. RESULTS: The 50 patients had an average age of 70.8 years; 27 (54%) were female. Amplicons for human beta-globulin, but not for cytomegalovirus, were produced for all tissue samples. The PCR results for B19 agreed in 29 of 30 samples tested by our institution and by the CDC (97% agreement; kappa = 0.9). A comparison of the B19 DNA analysis and the results of TAB indicated a statistically significant association between histologic evidence of GCA and the presence of B19 DNA in TAB tissue (chi2 = 10.38, P = 0.0013). CONCLUSION: These findings suggest that B19 may play a role in the pathogenesis of GCA.

Aged↗
PubMed1998

Malignant tumors of the kidney, brain, and soft tissues in children and young adults with the tuberous sclerosis complex.

BACKGROUND: The tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by seizures, mental retardation, and benign tumors of the brain, heart, skin, and kidney. Malignant tumors also can occur in patients with tuberous sclerosis, particularly in the kidney, although they occur less frequently than benign tumors. The types of malignancy that occur in TSC have not been characterized fully. METHODS: Clinical and pathologic features of 8 malignant tumors from 6 TSC patients ranging in age from 22 months to 21 years are reviewed. Six tumors were renal, one was from the inguinal region, and one was from the brain. The tumors were analyzed for loss of heterozygosity (LOH) in the chromosomal regions of the TSC1, TSC2, and VHL genes. RESULTS: Three patients (ages 7, 8, and 20 years) had renal cell carcinomas (RCCs). Two of these patients had multifocal RCCs. All three patients with RCC also had prominent multifocal dysplasia of renal cyst epithelium. Two patients (ages 20 and 21 years) had malignant angiomyolipomas (1 renal and 1 inguinal). One patient (age 22 months) had a Grade 4 giant cell astrocytoma (glioblastoma multiforme). LOH in the region of the TSC2 gene was found, either in the malignant tumor or in benign tumors, in all five patients whose DNA could be analyzed. CONCLUSIONS: Children with TSC, as well as adults with the disease, are at risk for developing malignant tumors. Two types of renal malignancy occur in TSC: RCC, which appears to arise from dysplastic renal cyst epithelial cells, and malignant angiomyolipoma. Tumors cytologically similar to malignant angiomyolipomas also may occur at extrarenal sites. LOH analyses suggest that the majority of patients with TSC who develop malignant tumors have germline TSC2, rather than TSC1, gene mutations.

Adult↗
PubMed1998

[Matrix gene expression pattern as indicators of the biology of cartilage-forming tumors].

Mesenchymal cells can be characterized by the expression of specific sets of extracellular matrix (ECM) proteins. The aim of our study was to identify such expression pattern in cartilage-forming tumours in order to elucidate the biology of these neoplasms. In situ hybridisation and immunohistochemistry for various ECM components were performed on enchondromas, conventional chondrosarcomas of various grades and dedifferentiated chondrosarcomas. Chondroid areas of all investigated neoplasms showed strong expression of cartilage collagen types II and IX and aggrecan core and link protein. Focally, also the expression of other collagen subtypes such as collagen type X and collagen types I and III was observed. Non-chondroid areas of dedifferentiated chondrosarcomas lacked any expression of the cartilage-typical gene products and were instead positive for interstitial collagen types I, III, and VI. The hallmark of all investigated cartilaginous neoplasms was the expression of the chondrocyte-typical genes. Neoplastic chondrocytes showed the differentiation facettes similar to their physiological counterparts resulting in the high heterogeneity, which is characteristic for chondrogenic neoplasms. A different biology is suggested for dedifferentiated chondrosarcomas, in which the "dedifferentiated" portion is proposed to have a separate (e.g. fibroblastic) mesenchymal origin.

Bone Neoplasms↗
PubMed1997

Systemic amyloidosis with temporal artery involvement mimicking temporal arteritis.

A 77-year-old man presented with jaw claudication, arthralgias and myalgias, weight loss, marked fatigue, and thickened temporal arteries. No vasculitis was seen on the temporal artery biopsy specimen, but amyloidosis was suspected and confirmed with Congo red staining. Subsequent bone marrow biopsy revealed multiple myeloma. Although the patient initially was thought to have temporal arteritis, the results of temporal artery biopsy directed further investigations that led to the diagnosis of systemic amyloidosis. Systemic amyloidosis should be considered in the differential diagnosis when patients, especially men, present with clinical findings suggestive of temporal arteritis but without evidence of vasculitis in temporal artery biopsy specimens.

Aged↗
PubMed1996

Tuberous sclerosis-associated renal cell carcinoma. Clinical, pathological, and genetic features.

The tuberous sclerosis complex (TSC) is a multisystem autosomal dominant disorder characterized by seizures, mental retardation, and hamartomas. Patients with TSC have been reported to develop renal cell carcinomas (RCC) with increased frequency, an observation that is supported by the Eker rat model. To address the role of the tuberous sclerosis tumor suppressor genes in the pathogenesis of RCC, we studied six TSC-associated RCCs. Our findings suggest that some TSC-associated RCCs have clinical, pathological, or genetic features distinguishing them from sporadic RCC. Clinically, the TSC-associated tumors occurred at a younger age (mean, 36 years) than sporadic tumors and occurred primarily in women. Four of the six patients died of metastatic disease. Pathologically, five tumors displayed clear cell morphology. Of those five, two had high-grade spindle cell areas and one had granular cell histology in addition to the clear cell areas. A sixth tumor was anaplastic throughout. Four of the six tumors immunostained positively for a melanocyte-associated marker, HMB-45. HMB-45 positivity has been seen in two other TSC lesions: renal angiomyolipomas and pulmonary lymphangiomyomatosis. Five tumors were analyzed for loss of heterozygosity. Two had loss of heterozygosity on chromosome 9q34 and one had loss of heterozygosity on chromosome 16p13. We conclude that TSC-associated RCCs occur at an earlier age than sporadic RCCs, that some TSC-associated renal carcinomas have a different immunophenotype than sporadic RCCs, and that the TSC tumor suppressor genes may play a specific pathogenic role in these tumors.

Adult↗
PubMed1994

Thoracic aortic aneurysm and rupture in giant cell arteritis. A descriptive study of 41 cases.

OBJECTIVE: To determine the features and outcomes of patients with giant cell arteritis (GCA) who have aneurysms or rupture of the thoracic aorta. METHODS: Patients with GCA seen over a 40-year period who had aneurysms and/or rupture of the thoracic aorta were identified by assistance of a computerized indexing system. The presence of thoracic aortic aneurysms (TAA), with or without aortic valve insufficiency (AI), was determined by radiographs, computed tomography scans, and ultrasound studies of the thorax, angiograms of the aorta, and postmortem examination. RESULTS: Ten men and 31 women with GCA were found to have TAA and/or rupture. Three developed TAA before GCA was diagnosed, 5 developed aortic findings near the time of the diagnosis, and 33 after the diagnosis of GCA (median of 7 years after diagnosis). Sixteen patients developed acute aortic dissection, which caused death in 8. Nineteen patients also had AI due to aortic root dilation, 15 of whom developed congestive heart failure. Eighteen patients underwent 21 surgical procedures for TAA resection and/or aortic valve replacement or repair. Aortitis was documented histologically in 10 cases. CONCLUSION: Thoracic aortic complications in GCA are associated with serious outcomes that have been underrecognized and may be fatal. Physicians should be alert to the development of these complications at any time in the course of GCA, even many years after usual symptoms have subsided.

Adrenal Cortex Hormones↗
PubMed1994

Primary systemic amyloidosis presenting as giant cell arteritis and polymyalgia rheumatica.

Primary systemic amyloidosis may present with features suggesting a vasculitis, including giant cell arteritis (GCA) and polymyalgia rheumatica (PMR). In this report, we describe the clinical characteristics, temporal artery biopsy findings, and the response of vascular and musculoskeletal symptoms to corticosteroid therapy in 4 patients with primary systemic amyloidosis who presented with manifestations of GCA or PMR.

Aged↗
PubMed1993

Chordoma of the mobile spine. A clinicopathologic analysis of 40 patients.

BACKGROUND: Chordomas are lobulated neoplasms composed of physaliphorous cells and their precursors; some have atypical, epithelioid, or spindle cell features. Fewer than one-sixth of chordomas arise in the mobile (cervical, thoracic, or lumbar) spine. Forty-eight percent originate in the sacrococcygeal region and 39% in the sphenoocciput. METHODS: The study included 40 patients, 27 men and 13 women (2:1), with chordoma of the mobile spine. Their clinical and histopathologic features are described. RESULTS: Nineteen tumors (48%) were located in the cervical spine, 7 (17%) in the thoracic spine, and 14 (35%) in the lumbar area. Most patients underwent subtotal removal of the tumor and postoperative irradiation. Variations in histologic appearance, including an occasional chondroid background, did not affect biologic behavior. Twenty-three patients (58%) were alive 5 years after surgery. Eventually, 25 patients (63%) died of tumor. Metastasis developed in two patients (5%). In contrast to some other studies metastasis was a rare occurrence. CONCLUSION: Chordoma of the mobile spine is a slow-growing, recurring neoplasm of low metastatic potential that incapacitates by locally aggressive growth.

Adult↗
PubMed1988

T cell populations in the lacrimal gland during aging.

The present study examined the influence of age and gender on T cell populations in the lacrimal gland. Lacrimal (exorbital) glands were obtained from male and female rats at 19 days (pre-puberty), 9 weeks (adult) and 14 months (mid-life) of age and tissues were processed for T cell subset identification. In females, the density of total (W3/13+ and OX 19+), helper/inducer (W3/25+) and suppressor/cytotoxic (OX 8+) T cells underwent a significant increase in tissues from before, to after puberty. Following this rise, the density of all T cell populations decreased in glands from young adult to midlife females. This pattern of accumulation contrasted with the T cell profile presented by glands from males: T cell densities appeared unaffected from 19 days to 9 weeks of age, and then either declined (OX 19+, W3/25) or remained unchanged (W3/13+, OX 8+) in tissues of 14 month rats. An influence of gender on the distribution of T cells was also apparent if results were corrected for age-associated variations in lacrimal gland weight. Thus, the absolute number of all T cell populations rose dramatically in glands of both sexes from pre- to post-puberty. However, from 9 weeks to 14 months of age, the total content of W3/13+, OX 19+, W3/25+ and OX 8+ lymphocytes decreased 2-fold in glands of females, but did not vary in tissues of males. Of interest, the number of W3/25+ and OX 8+ cells was analagous in all age groups examined. Moreover, the combined total of W3/25+ and OX 8+ cells was greater than that of W3/13+ or OX 19+ cells at every age.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Cytologic findings in stage I adenocarcinoma of the lung: implications for the detection of early lung cancer.

Preoperative cytologic examinations were performed on bronchial material from 92 patients with postsurgical (pathologic) stage I (American Joint Committee) adenocarcinoma of the lung. All patients were followed up for at least 5 years or until death; thus, cases of adenocarcinoma metastatic to the lungs were virtually excluded. Only 22 patients (24%) had abnormal preoperative cytologic findings. This low cytologic sensitivity is ascribed to the small size and peripheral location of the tumors. Large lesions of high histologic grades were more likely to have positive preoperative cytologic findings than small, well-differentiated ones.

Adenocarcinoma↗