Biomedical subjects

J Tashjian

Publications and source records attributed to J Tashjian.

6 recordsLinked to original sources

PubMed2001

Defining radiographic criteria for flexion-extension studies of the cervical spine.

STUDY OBJECTIVE: We sought to describe and measure 3 radiographic variables in normal male volunteers and determine whether these variables could be useful in establishing more objective radiographic criteria for evaluation of flexion-extension studies of the cervical spine. In addition, we hypothesized that patients with a normal cervical spine should not have greater than 2 mm of subluxation present with flexion or extension. METHODS: A prospective, observational study of normal male volunteers between the ages of 18 and 40 years was performed. We obtained radiographs of all participants in neutral, flexion, and extension positions and measured the amount of subluxation and interspinous distance, as well as the degree of vertebral angulation between C3 and C7. RESULTS: One hundred male volunteers were included in the study. Subluxation during flexion (compared with neutral) was greater than 2 mm in none of the participants at each level from C3 to C7 (95% confidence interval [CI] 0 to 3.6); subluxation in extension was greater than 2 mm in one participant at one level from C3 to C4 (95% CI 0 to 5.5) and none of the participants at each of the remaining 3 levels from C4 to C7 (95% CI 0 to 3.6). Comparing flexion with the neutral position, the mean vertebral angulation and SD were 24.2 degrees and 13.3 degrees, and the 95% certainty interval (CEI) was -1.9 to 50.2. Comparing extension with the neutral position, the mean vertebral angulation was 14.1 degrees, with an SD of 13.3 degrees, and the 95% CEI was -4.6 to 32.8. The mean change in interspinous distance between the neutral position and flexion varied from 1.2 to 4.6 mm (SD 1.7 to 2.4 mm), depending on the level of cervical spine studied. When comparing the neutral position and extension, the mean change in interspinous distance varied from 1.2 to 2.2 mm (SD 1.7 to 1.9). CONCLUSION: Currently, there are no clinically validated criteria for evaluating flexion-extension studies of the cervical spine. Our study suggests that subluxation greater than 2 mm in men 18 to 40 years of age may be a useful variable for further study as an indicator of ligamentous injury. Interspinous distance and vertebral angulation appear less likely to have useful clinical application.

Adolescent↗

PubMed1994

Pathogenesis of pulmonary fibrosis: platelet-derived growth factor precedes structural alterations in the Hermansky-Pudlak syndrome.

Peptides that modulate mesenchymal cell function have been detected in the fibrotic lung disorders once physiologic dysfunction is present. Despite this close association with manifest disease, their role in initiating alveolar remodeling remains unknown. We examined the hypothesis that one potent peptide, platelet-derived growth factor (PDGF), would be present at the alveolar surface before the onset of physiologic dysfunction in patients in whom pulmonary fibrosis subsequently develops. Bronchoalveolar lavage and physiologic assessment were performed in asymptomatic patients with the Hermansky-Pudlak syndrome (n = 30), obligate heterozygous (n = 9), and normal volunteers (control group). Lavage cell number and profile were normal, but alveolar macrophages demonstrated characteristic autofluorescence and ultrastructural features of ceroid. Lavage fluid from physiologically normal patients with Hermansky-Pudlak syndrome and from those with occult restrictive disease demonstrated two PDGF-related peptides (14 kd and 38 kd). Radioligand binding and fibroblast proliferation assay demonstrated that the peptides were functional. By immunoassay the concentration of PDGF in lavage fluid was six times greater than control values (p < 0.01). In situ hybridization together with bioassay indicated that alveolar macrophages were one cellular source of PDGF. Similar results were obtained for heterozygotes. These data identify macrophage-derived PDGF peptides as important candidate molecules in the initiation of alveolar remodeling in the fibrotic lung disorders.

Adolescent↗

PubMed1989

Reversible hyperinflation in emphysema.

Pulmonary emphysema results in hyperinflation of the lungs and concomitant changes in the configuration of the thoracic cavity. We describe a patient who underwent bilateral lung transplantation for emphysema due to alpha 1 antitrypsin deficiency. Dramatic changes in chest dimensions and configuration occurred following transplantation, demonstrating the dynamic and reversible nature of the thoracic cavity abnormalities of emphysema.

Adult↗

PubMed1989

Primary squamous cell carcinoma of the breast: mammographic findings.

Primary squamous cell carcinoma of the breast is a rare lesion. Mammographic findings usually suggest malignancy and include an irregular, lobulated mass with poorly defined borders. Microcalcification is not a prominent finding. Tumor size is important in determining long-term outcome, and patients usually die from distant metastases.

Breast↗

PubMed1988

The role of plain films, CT, tomography, ultrasound, and percutaneous needle aspiration in the diagnosis of inflammatory lung disease.

Traditionally, plain film chest radiography has been the mainstay in the roentgenographic evaluation of infectious disease in the chest. Plain film tomography has augmented the chest radiograph in the detection of cavitation and in evaluation of the bronchial tree. Newer imaging modalities including ultrasound, which evaluates the pleural space, and computerized tomography (CT), which examines the lung parenchyma, mediastinum, pleura, and chest wall, have further aided in diagnosis. Finally, percutaneous aspiration of the lung or pleural space under radiologic guidance now allows specific diagnoses to be made more frequently and with fewer complications.

Abscess↗

PubMed1986

Modern imaging and endoscopic biopsy techniques in Egyptian mummies.

Egyptian mummies have been popular subjects of radiographic investigation since 1896. Computed tomography (CT) and magnetic resonance imaging (MRI) have recently been added to the growing list of modern techniques used to study these relics. The Minnesota Mummy Project was organized to examine four well preserved Egyptian mummies dating from the XVIIIth (1575-1308 B.C.) and XXVth (715-663 B.C.) Dynasties. Plain radiographs and CT scans were obtained on all specimens. One individual was selected for additional endoscopic and microscopic correlation with CT findings in the thoracic cavity. The collapsed heart was identified by CT. A percutaneous biopsy of the heart was then performed with a flexible fiberoptic endoscope, passed through a small hole drilled into the chest wall. Microscopy of prepared ventricular specimens revealed striated muscle fibers consistent with myocardium. These results emphasize the utility of CT as a noninvasive paleoradiologic tool. Another mummy was examined by MRI to search for minute quantities of residual moisture possibly trapped within the desiccated tissues. Only a free-induction-decay signal could be obtained, but this was insufficient to generate an image. Thus, it appears that present MRI is not suitable for the paleopathologic investigation of dehydrated structures.

Biopsy↗