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Biomedical subjects

M Sarwar

Publications and source records attributed to M Sarwar.

117 records · Page 7Linked to original sources
PubMedDate not supplied

Experimental cord stretchability and the tethered cord syndrome.

Much remains to be learned about the embryology and pathophysiology of the "tethered cord syndrome." Of particular importance in tethered cord syndrome is spinal cord stretchability and its relation to resultant cord dysfunction. In this study, cord elongation was observed in fresh fetuses and in animals by applying weights or forceps traction at the conus medullariscauda equina region. The results show that maximum cord elongation occurs in the lumbar region, some occurs in the thoracic area, and minimal to no elongation occurs in the cervical region. These results are concordant with clinically observed lumbosacral cord dysfunction and oxidative and electrophysiologic impairment of the lumbosacral cord in tethered cord syndrome as shown by other investigators.

Animals↗
PubMedDate not supplied

Skull phylogeny: an investigation using radiography and high-resolution computed tomography.

To demonstrate the phylogenetic changes that have led to the current form of the human skull, dried skulls of various representative vertebrates were examined using plain radiography and high-resolution computed tomography. The latter was chosen rather than pluridirectional tomography in anticipation of its future role as the major method for imaging the skull base. The phylogenetic history of the human skull is reviewed by considering separately the evolution of the calvarium, zygomatic arch, palate, jaw, and skull base.

Anatomy, Comparative↗
PubMedDate not supplied

Primary tethered cord syndrome: a new hypothesis of its origin.

Primary tethered cord syndrome is defined as low placement of the spinal cord and thickened filum terminale with associated anomalies. This definition excludes anomalies concomitant with overt myelomeningocele and spinal cord tethering secondary to myelomeningocele repair. Embryologically, the primary tethered cord syndrome is an entirely different entity from overt myelomeningocele and associated Arnold-Chiari type II malformation, but its origins have not been satisfactorily explained. The authors postulate that primary tethered cord syndrome is a manifestation of local dysmorphogenesis of all three germ layers at the lumbosacral area, possibly triggered by a hemorrhagic, inflammatory, or some other local lesion occurring in embryogenesis.

Animals↗
PubMedDate not supplied

High-resolution computed tomographic appearance of normal cochlear aqueduct.

Computed tomographic (CT) scans of 37 patients with normal adult cochlear aqueducts were selected for retrospective analysis. Usually, only the inferomedial part of the cochlear aqueduct could be seen on axial CT. The sizes of the external cochlear aqueduct opening were tabulated, and they did not vary significantly with age or gender. The average width was 2.9 mm. Of the configurations found, the most common was the funnel (22 cases).

Adolescent↗
PubMedDate not supplied

Computed tomography of dural sinus thrombosis.

For 150 years, the variable clinical appearance of dural sinus thrombosis has plagued clinicians. Computed tomography (CT) has alleviated much of the difficulty in making this diagnosis. A high density lesion in the involved sinus on precontrast scans and a filling defect in the sinus on postcontrast scans were the most frequently observed CT abnormalities in 12 patients with sinus thrombosis. Other findings include the "cord" sign and diffuse cerebral edema. Thrombosis of the superior sagittal sinus, transverse sinus, or sigmoid sinus can occur as an isolated event or in association with other disease entities and may cause no neurologic impairment.

Adult↗
PubMedDate not supplied

Comparative study of positron emission tomography and quantitative digital radiography (QDR) in detecting effects of aging and diet on bone metabolism of guinea pig.

The purpose of this study was to compare positron emission tomography and quantitative digital radiography (QDR) in detecting the effects of aging and diet on bone metabolism. Bone imaging of guinea pigs was performed with fluorine-18 fluoride ions using a high-resolution animal PET system to analyze bone metabolism quantitatively in different age groups of guinea pigs, young (8 weeks), adult (36 weeks), and aged groups (96 weeks), and also in a dietary manipulation group (low calcium and low vitamin D3 diet for 1, 2, and 3 weeks). A three-compartment kinetic model was applied for the analysis of bone metabolism to evaluate the rate constant (K, K1-K4). There was a significant difference in K-constant between the young and other groups. The K-constant was higher (0.100+/-0.005 ml/min/ml) in the young group than in adults (0.028+/-0.001 ml/min/ml) (p < 0.001) and the aged group (0.047+/-0.020 ml/min/ml). This high value of the K-constant in the young group indicates high turnover in bone metabolism, but there was no significant difference between the adult and aged groups. Bone mineral density (BMD) was lower in the young group (0.15+/-0.026 g/cm2) than in the adult (0.230+/-0.021 g/cm2) (p < 0.001) and aged groups (0.26+/-0.03 g/cm2). There was no significant difference in BMD between the adult and aged groups. Although there was no difference in BMD between the control and dietary manipulation groups, PET study revealed a significant difference in K-constant between them (0.028+/-0.001 vs. 0.090+/-0.009 ml/min/ ml) (p < 0.001). The quantitative skeletal dynamic PET study with 18F fluoride ions was more sensitive and superior in the early detection of metabolic disorders in bone disease than QDR.

Aging↗
PubMedDate not supplied

99mTc-labeled chimeric anti-NCA 95 antigranulocyte monoclonal antibody for bone marrow imaging.

Chimeric mouse-human antigranulocyte monoclonal antibody (ch MAb) against non-specific cross-reacting antigen (NCA-95) was labeled with 99mTc (using a direct method) and 125I (using the chloramine T method), and its binding to human granulocytes and LS-180 colorectal carcinoma cells expressing carcinoembryonic antigen on their surfaces, cross-reactive with anti-NCA-95 chimeric monoclonal antibody, increased in proportion to the number of cells added and reached more than 80% and 90%, respectively. In biodistribution studies, 99mTc and 125I-labeled ch anti-NCA-95 MAb revealed high tumor uptake, and the tumor-to-blood ratio was 2.9 after 24 hours. The tumor-to-normal-organ ratio was also more than 3.0 in all organs except for the tumor-to-kidney ratio. Scintigrams of athymic nude mice confirmed the results of biodistribution studies that showed higher radioactivity in tumor and kidney of the mice administered with 99mTc-labeled ch MAb. A normal volunteer injected with 99mTc-labeled ch anti-NCA-95 antigranulocyte MAb showed clear bone marrow images, and a patient with aplastic anemia revealed irregular uptake in his lumbar spine, suggesting its utility for bone marrow scintigraphy and for the detection of hematological disorders, infections, and bone metastasis.

Anemia, Aplastic↗