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Biomedical subjects

A M Kurt

Publications and source records attributed to A M Kurt.

At least 37 records · Page 2Linked to original sources
PubMed1997

Neoplastic invasion of the laryngeal cartilage: reassessment of criteria for diagnosis at CT.

PURPOSE: To evaluate eight different diagnostic criteria to help detect neoplastic invasion of laryngeal cartilage at computed tomography (CT). MATERIALS AND METHODS: In a prospective series, 111 patients with carcinoma of the larynx or hypopharynx underwent thin-section, contrast material-enhanced CT before total or partial laryngectomy. The following CT criteria were evaluated: extralaryngeal tumor, sclerosis, tumor adjacent to nonossified cartilage, serpiginous contour, erosion or lysis, obliteration of marrow space, cartilaginous blowout, and bowing. Histologic findings were correlated with findings on CT scans obtained at each level. RESULTS: Histologically, 122 of 412 cartilages were invaded. Depending on the diagnostic criteria and each specific cartilage, there was great variation in sensitivity (7%-83%) and specificity (40%-100%). Sclerosis was the most sensitive criteria in all cartilages but often corresponded to reactive inflammation in the thyroid cartilage. Extralaryngeal tumor and erosion or lysis yielded the highest specificity. Tumor adjacent to nonossified cartilage, serpiginous contour, and obliteration of marrow space were specific although not sensitive signs of invasion in the arytenoid and cricoid cartilage and were nonspecific in the thyroid cartilage. Blowout and bowing were not useful. Selection of the appropriate combination of criteria enabled an overall sensitivity of 91% (associated specificity, 68%) or an overall specificity of 79% (associated sensitivity, 82%). CONCLUSION: Detection of neoplastic cartilage invasion with CT greatly depended on the appropriate use of individual and combined CT criteria.

Adult↗
PubMed1997

Pulmonary fibrosis with predominant CD8 lymphocytic alveolitis and anti-Jo-1 antibodies.

Interstitial lung disease (ILD) is a complication of polymyositis (PM) and dermatomyositis (DM). It often manifests itself in association with myositis-specific antisynthetase autoantibodies, among which anti-Jo-1 antibodies are the most commonly encountered. In contrast, ILD associated with anti-Jo-1 antibodies without muscle involvement is rare and not well characterized. We report four patients presenting with ILD associated with anti-Jo-1 antibodies. Histological findings of transbronchial biopsies disclosed a pattern consistent with nonspecific interstitial pneumonitis, a CD8+ lymphocytosis was found in bronchoalveolar lavage. Only one of these patients developed an "antisynthetase syndrome" with PM, after nearly 2 yrs of severe ILD. The clinical conditions of all four cases showed stabilization or improvement when cyclosporine was added to their immunosuppressive treatment. These cases confirm that a CD8+ lymphocytic interstitial lung disease may be the first, and sole manifestation of autoimmune disease associated with anti-Jo-1 antibodies. Furthermore, they suggest that this form of interstitial lung disease apparently has a poor response to steroids and cytotoxic drugs, but may respond to moderate doses of cyclosporine and azathioprine in addition to low doses of steroids.

Aged↗
PubMed1997

Frequent p16INK4 (MTS1) gene inactivation in testicular germ cell tumors.

The molecular mechanisms responsible for the development of testicular germ cell tumors (GCTs) have not as yet been elucidated. The aim of the present study was to determine whether genetic alterations of p16INK4 (MTS1) and/or cyclin-dependent kinase 4 (CDK4) occur in the genesis of these tumors. We have analyzed these two genes in 29 testicular GCTs, seminomas, and nonseminomas. None of the tumors showed either p16INK4 or CDK4 mutations. Only 1 of the 29 GCTs displayed loss of heterozygosity of the p16INK4 gene. No homozygous deletions of p16INK4 were detected. Evidence of hypermethylation of p16INK4 exon 1, however, was demonstrated in 13 of the 26 (50%) GCTs analyzed. Tumor samples having exon 1 of p16INK4 methylated expressed significantly lower levels of p16INK4 mRNA, as analyzed by reverse transcriptase polymerase chain reaction. These results suggest that p16INK4 inactivation plays a role in the genesis of GCTs.

Adolescent↗
PubMed1997

Phenotypic modulation of alveolar myofibroblasts in transplanted human lungs.

We examined 33 successive pulmonary biopsy specimens from nine patients who underwent pulmonary transplantation; they were compared to "normal" lung tissue selected from routine transbronchial biopsy material and also to surgical biopsy specimens from a previously reported study. We used as controls the three successive biopsy specimens from Patient 7, in whom rejection reaction did not develop, and the two specimens from Patient 6, who had pneumonia caused by cytomegalovirus. The material was embedded in paraffin, and the sections were stained by hematoxylin and eosin, periodic acid-Schiff, Masson's trichrome, and Gomori's silver stains. They were also immunostained for alpha-smooth muscle actin (alpha-SMA), desmin, transforming growth factor beta1, tumor necrosis factor alpha, keratin, CD3, CD20, CD68, and HLA-dr. In all of the lung tissue from patients in whom a rejection reaction developed, alveolar myofibroblasts (MFs) expressed alpha-SMA. Sometimes, alpha-SMA expression appeared before the classical manifestations of rejection reaction. MFs labeled by alpha-SMA antibody did not express desmin; alveolar septa containing alpha-SMA-positive cells were frequently lined by transforming growth factor beta1 and, occasionally, tumor necrosis factor alpha-laden Type II pneumocytes. In lung tissue (from successive biopsies) that did not show evidence of rejection reaction, alveolar MFs did not express alpha-SMA. Our findings demonstrate that modulation of alveolar MFs is one of the manifestations of rejection in transplanted lungs; furthermore, they suggest that alpha-SMA staining might be useful in predicting rejection reaction before the classical cellular events occur.

Acute Disease↗
PubMed1996

Microsatellite alterations in plasma DNA of small cell lung cancer patients.

Microsatellite instability is an important characteristic of many tumor types especially those associated with hereditary non-polyposis colorectal carcinoma (HNPCC) syndrome. Microsatellite alterations in 50% of primary small cell lung carcinoma (SCLC) have been found. These alterations were also found in the sputum. Because neoplastic characteristics such as decreased strand stability9 and ras mutations have been found in the plasma DNA of cancer patients, we looked for microsatellite alterations in the plasma of SCLC patients. A microsatellite alteration was present in 16 out of 21 (76%) SCLC tumors and in 15 out of 21 (71%) plasma samples. In one case, the alteration was present only in the plasma DNA. If confirmed in larger studies, microsatellite analysis of plasma DNA might constitute a new tool for tumor staging, management and, possibly, detection.

Adult↗
PubMed1996

Germ cell tumors of the testis overexpress wild-type p53.

Several recent studies have suggested that testicular germ cell tumors express high levels of wild-type p53 protein. To clarify and confirm this unexpected result, we have investigated seminomatous and nonseminomatous germ cell tumors at the genomic, mRNA, and protein levels. Thirty-five tumors were examined for p53 overexpression using antibodies directed against the p53 (PAb1801, PAb240, and CM1), mdm2 (IF2), and p21Waf1/Clp1 (EA10) proteins. Thirty-two tumors were screened for p53 mutations by single-strand conformation polymorphism analysis. Eighteen tumors were screened with a functional assay that tests the transcriptional competence of human p53 protein expressed in yeast. On frozen sections, 100, 65, 35, 73, and 0% of tumors reacted with the CM1, PAb240, PAb1801, IF2, and EA10 antibodies, respectively. No p53 mutations were detected by single-strand conformation polymorphism or by functional assay. The fact that many tumors overexpress wild-type p53 but not mdm2 rules out mdm2 overexpression as a general explanation for the presence of wild-type p53 in these tumors. The absence of p21 overexpression suggests that p53 may be unable to activate transcription of critical target genes, which may explain why the presence of wild-type p53 is tolerated in this tumor type, although the mechanism for this transcriptional inactivity remains to be established.

Cyclin-Dependent Kinase Inhibitor p21↗
PubMed1995

Beta-adrenergic mechanisms in the nasal mucosa vascular bed.

In thiopentone-anesthetized mature pigs (n = 7), local intra-arterial infusion of the beta 2-adrenoceptor agonists terbutaline and salbutamol and the beta 3-agonist BRL 37344 induced dose-dependent increases in nasal arterial blood flow (BF) and volume of the nasal mucosa (reflecting capacitance vessel function). Increases were also found in the laser Doppler flowmeter signal, reflecting superficial mucosal BF. In contrast to terbutaline and salbutamol, BRL 37344 showed marked effects on volume. Pretreatment with the beta-adrenoceptor blocker propranolol significantly reduced the vasodilatory effects of terbutaline and salbutamol, whereas the BF increase evoked by BRL 37344 was not affected. Exogenous noradrenaline (NA) induced in vitro dose-dependent contractions of human nasal mucosa biopsies obtained from patients with non-allergic chronic rhinitis (n = 21) or non-allergic nasal polyposis (NANP, n = 16). On a molar basis, the contractile effect of NA was significantly greater in nasal mucosa samples without histological abnormalities when compared to biopsies with abundant inflammatory cells and edema within the submucosa. In the presence of propranolol, the vasoconstrictor effect of NA was significantly enhanced in biopsies with abundant inflammatory cells obtained from patients with NANP (P < 0.01). This observation suggests the possible occurrence of a beta 2 hyper-reactivity in the nasal mucosa of patients with NANP. After precontraction in a Krebs-Ringer solution with 50 nM K+, all nasal biopsies studied showed dose-dependent relaxation to terbutaline, salbutamol and BRL 37344. This relaxant effect was markedly reduced after pretreatment with propranolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Antagonists↗
PubMed1995

Neutral endopeptidase activity and concentration of sensory neuropeptide in the human nasal mucosa.

Human nasal mucosa biopsy samples were studied by biochemical and histological methods to determine whether the concentration of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) as a marker of sensory nerves was dependent on the activity of neutral endopeptidase-like enzyme (NEP-LE). Mucosal samples from the middle turbinate were obtained from 32 patients undergoing functional endoscopic nasal surgery for non-allergic chronic rhinosinusitis. The degree of symptoms related to nasal obstruction, rhinorrhea and headaches was recorded. The number of inflammatory cells in each biopsy sample was evaluated by conventional histopathological examination. CGRP-LI was measured by radioimmunoassay. The activity of NEP-LE was evaluated in vitro using [3H] Leu5-enkephalin as substrate. A good correlation was observed between increased concentrations of CGRP, abundant inflammatory cells and the intensity of symptoms (R2 = 0.80). A low activity of NEP-LE was associated with a high concentration of both inflammatory cells and CGRP, suggesting that NEP-LE activity was reduced during inflammation. These observations further support the hypothesis that reduced degradation of sensory neuropeptides could be involved in the pathophysiological mechanisms of non-specific chronic rhinosinusitis.

Calcitonin Gene-Related Peptide↗
PubMed1995

Calcification of the tibialis posterior tendon: a case report and literature review.

The tibialis posterior muscle and tendon are subject to a number of pathological conditions and injuries that have recently received much attention in the literature. Because of its function as a main stabilizer of the subtalar complex against hindfoot valgus and forefoot pronation, the mechanical demand on the posterior tibial tendon is high. Problems with dislocation, tenosynovitis, rupture, and laceration have all been described with this tendon. In this report, we present a case of dysfunction of the posterior tibial tendon associated with chronic tendinitis and intratendinous calcifications. After removal of the calcifications, the patient became asymptomatic and returned to work. Proposed etiologies of these calcifications are discussed.

Adult↗
PubMed1994

[Endocrine tumors of the pancreas: immunohistochemical and clinical correlation].

24 out of 28 cases of pancreatic endocrine tumors were studied by immunohistochemistry. They comprised 11 insulinomas, 3 gastrinomas, 1 VIPoma, 1 glucagonoma and 8 with no endocrine syndrome. 7 patients presented metastasis by the time of diagnosis. In 14 out of 16 cases of tumors with endocrine syndrome, there was a good correlation between clinical syndrome and histological findings. Half of these neoplasms showed positivity for more than one hormone but only one cell type predominated which was responsible for the endocrine syndrome. The other hormonal stainings had no clinical expression. Bouin- or Dubosq-fixed samples allowed a better immunohistochemical analysis than for formalin-fixed tissues. Chromogranin was found to be the best general marker for endocrine tumors. Immunohistochemical staining, when positive, generally showed a diffuse coloration of the cytoplasm. Sometimes it resembled a "coup d'ongle" or a single granular staining, but its significance is still unknown.

Adult↗
PubMed1994

Case report 860: Bacillary angiomatosis of the calcaneum.

Bacillary angiomatosis (BA) is newly reported infectious disease observed mainly in HIV-infected patients, caused by a small gram-negative bacillus of the Rochalimea genus. From a purely dermatological presentation similar to that of Kaposi's sarcoma, it may evolve into a systemic disease. Bone lesions seem fairly frequent. We report a case of an isolated osteolytic lesion due to the BA bacillus.

AIDS-Related Opportunistic Infections↗
PubMed1993

Computed tomography and fine-needle aspiration cytology for preoperative evaluation of cystic tumours of the pancreas.

Cystic neoplasms of the pancreas are rare. They may present as a mucinous (malignant or potentially malignant) tumour or as benign serous cystadenoma. Accurate preoperative diagnosis is therefore essential, as an asymptomatic serous tumour may safely be followed clinically for years, whereas mucinous tumours require aggressive surgery. Thirteen patients with cystadenoma and cystadenocarcinoma of the pancreas were reviewed and how best to improve the rate of preoperative diagnosis was considered. Fine-needle aspiration cytology and computed tomography enable accurate preoperative distinction between mucinous and serous cystic tumours of the pancreas.

Adult↗
PubMed1993

Chondroblastoma.

Chondroblastoma of the bone is a benign tumor that has well-characterized radiographic and histologic features. It tends to affect the epiphyseal ends of long bones in men during the second and third decades of life. The tumor is located more frequently at other sites in older patients. The treatment of choice is complete curettage with bone grafting, which in our series provided local control in 82% of patients at 2 years' follow-up. Recurrent tumors usually can be treated in the same manner.

Adolescent↗
PubMed1992

Leiomyosarcoma of the pulmonary hilar vessels.

Leiomyosarcomas are uncommon tumors. They have a predilection for deep soft tissues, with a rare group arising in medium-sized or large veins, far less frequently in arteries. We report a case of a 63-year-old man, with an enlarging mass located in the left pulmonary hilar region which was discovered on a routine chest radiograph. Cytology of the sputum and bronchoscopic biopsies did not reveal any malignant cells. Over 5 months observation, there was a clear progression of the mass, and the patient finally underwent a left pneumonectomy which allowed the diagnosis of an intravascular leiomyosarcoma partially destroying major arteries and veins in the hilar region. A review of the literature reveals 67 cases of leiomyosarcoma involving the pulmonary artery. None of these cases had an associated venous pathology. The disease is found mainly in adult women. Clinical diagnosis is very difficult because most of the cases have no specific clinical signs; the major differential diagnosis is that of pulmonary thrombo-embolism. Prognosis depends on histological degree of the tumor and extent of the disease, metastases occur mainly in the liver, lung, and brain and less frequently in regional lymph nodes. Treatment is always surgical, chemotherapy is ineffective and the effectiveness of radiotherapy depends on the total dose of irradiation. Sarcomas of hilar blood vessels have a very poor prognosis with a one year survival estimated, from the onset of symptoms, at 20%.

Humans↗
PubMed1992

Colon carcinoma immunoscintigraphy by monoclonal anti-CEA antibody labeled with gallium-67-aminooxyacetyldeferroxamine.

Previous experimental results in nude mice showing that radiolabeling the monoclonal antibody anti-CEA 35 with 67Ga-aminooxyacetyldeferroxamine could give better tumor localization than radioiodination prompted us to initiate the present clinical study. The 67Ga-labeled antibody anti-CEA 35 (185 MBq, 0.7-1.7 mg) was injected preoperatively into 14 patients for colorectal carcinoma imaging. The same antibody labeled with 125I (3.7 MBq, 0.25 mg) was injected simultaneously to compare the 67Ga and 125I dose recoveries in surgical specimens. Twelve of 14 primary tumors gave a positive 67Ga scintigraph. The mean %ID/g recovered in all tumors 3-9 days after injection was significantly higher for 67Ga (0.019%) than for 125I (0.005%) (p < 0.001, paired t test). The tumor-to-normal tissue ratios were generally higher for 67Ga, with the exception of liver. We conclude that 67Ga-aminooxyacetyldeferroxamine improved immunoscintigraphy outside the liver, particularly in the pelvic region. We also show that deferroxamine infusion accelerates the excretion of 67Ga in eight patients and propose that this could lead to further improvement of immunoscintigraphy.

Aged↗
PubMed1990

Low-grade intraosseous osteosarcoma.

A study of 80 well-differentiated osteosarcomas, 16 from the Mayo Clinic files and 64 from our consultation files, revealed that males and females were about equally affected, most of the patients were young adults, and skeletal distribution was similar to the distribution seen in conventional osteosarcoma. Radiographs generally showed poor margination, suggestive of malignancy. Histologically, the tumors were composed of spindle cells with only minimal atypia. Some tumors had bone spicules similar to those seen in fibrous dysplasia. An invasive growth pattern was the most helpful feature in differentiating low-grade osteosarcoma from fibrous dysplasia. Initial treatment was highly variable. Local excision was almost always associated with recurrence. Wide excision was almost never followed by recurrence. The recurrent tumor was a high-grade, conventional osteosarcoma in 15% of the patients, and this was associated with a poor prognosis. Wide excision seems to be the treatment of choice for this very rare variant of osteosarcoma.

Adolescent↗
PubMed1990

Case report 628: Low-grade central osteosarcoma.

In summary, low-grade central osteosarcoma is a clinically recognizable rare subtype of osteosarcoma, representing 1.9% of all osteosarcomas found at the Mayo Clinic. The lesion is locally aggressive but also has the potential for metastasis, particularly after local recurrence. The tumor may be difficult to distinguish radiographically and histologically from benign conditions, particularly fibrous dysplasia. This difficulty has led to inadequate treatment. In most cases, a wide surgical margin achieved by either local resection or amputation should result in a cure. Because of the low metastatic potential of the initial lesion, there seems to be no need for adjuvant chemotherapy.

Adult↗