Biomedical subjects

J P Lin

Publications and source records attributed to J P Lin.

At least 91 records · Page 5Linked to original sources

PubMed1976

The usefulness of computed tomography during and after radiation therapy in patients with brain tumors.

Two years of experience with 100 patients in the serial study of brain tumors during and after radiation therapy has shown that computed tomography is useful in (a) depiction of regression or growth of primary and metastatic intracranial tumors, (b) recognition of untoward sequelae of radiation therapy, such as necrosis and edema, and (c) appreciation of changes in tumor density and ventricular size. Representation cases are discussed and illustrated.

Adult↗

PubMed1976

Role of computerized axial tomography in diagnosis and treatment of common neurosurgical problems of infancy and childhood.

Computerized axial tomography (CAT) is a new, highly accurate technique for studying the skull and intracranial contents. It is rapid enough to be utilized in acute emergencies and safe enough to be utilized for routine serial followups and evaluation of outpatients with equivocal findings. Because CAT can delineate the ventricular system without need for contrast agent, can distinguish clearly between hematoma and edema and can differentiate cystic from solid tumors, it finds wide application in the evaluation of neurological disease.

Brain Diseases↗

PubMed1976

Videodensitometry of cerebrospinal fluid pulsations.

Roentgen videodensitometry (RVD) during myelography is described in 13 patients with a variety of intraspinal lesions. Abnormalities in the RVD tracing are discussed and correlated with the type of spinal canal obstruction. Intramedullary, intradural and extradural processes may be differentiated by RVD.

Absorptiometry, Photon↗

PubMed1976

Chordoma: radiologic evaluation of 20 cases.

Experience with 20 cases of chordoma is summarized. Three of four intracranial tumors presented as sellar tumors. The clivus remained intact for 2, 3 1/2, and 4 years, respectively, in three patients despite extensive destructive lesions of the sellar region. Our data and those of others indicate that approximately half the patients with chordomas have erosion of the clivus at the time of initial medical evaluation. The other half mainly have sellar destructive lesions with or without associated clival erosion. Calcification occurs in 50%-70% of intracranial chordomas. A nasopharyngeal mass is present in one-third. Vertebral chordomas often involve two or more vertebrae, producing destructive lesions which often have a sclerotic rim. The intervertebral discs are commonly affected. A paraspinal soft tissue mass, half the time containing calcification, is often present. Sacral lesions are characterized by a midline destructive lesion, occasionally associated with expansion, with or without osteosclerosis. A firm, fixed, extrarectal, presacral mass which may contain calcification or fragments of bone is almost always present.

Adult↗

PubMed1976

Brain tumors studied by computerized tomography.

A brief description of the method and clinical application of CT is given. Various features and absorption values of different intracranial neoplasms are described and compared. The effects of CT on other special diagnostic procedures are discussed. It is emphasized that contrast medium enhancement significantly increases the sensitivity and specificity of the technique when applied to patients who have or are suspected of having cerebral neoplasms.

Brain Neoplasms↗

PubMed1975

The osseous and angiographic features of vertebral chordomas.

Eight cases of vertebral chordoma, exclusive of the sacrococcygeus, are presented. The conventional radiographic signs in descending order of importance in differential diagnosis are: destruction of multiple adjacent vertebral bodies; a paravertebral or precervical soft tissue mass; osteosclerosis, seen mainly at the periphery of the destructive lesion; and involvement of the intervening intervertebral disc space. All eight patients had a demonstrable intraspinal extension of chordoma on myelography. Four patients had complete blocks, two epidural in configuration, and two intradural in appearance - indicative of dural invasion by the neoplasm. Four patients had angiographic evaluation. Two demonstrated angiographic features usually associated with soft tissue malignant tumors. Angiography in all four cases was helpful in determining the full extent of the lesion, more so than either conventional radiography or myelography.

Adult↗

PubMed1975

Effects of temperature on diphosphopyridine nucleotide-linked isocitrate dehydrogenase from bovine heart. Aspects of the kinetics, stability, and quarternary structure of the enzyme.

A temperature-dependent conformational change of the active DPN-linked isocitrate dehydrogenase was observed. When initial reaction kinetic data were examined between 35 and 5 degrees, the Hill number (n) varied from 2 at higher to n approaching unity at lower temperatures, with an inflection point at 17 degrees. The presence of manganous isocitrate in the incubation media shifted the transition temperature for enzyme inactivation by 5,5'-dithiobis(2-nitrobenzoate) from 8-16 degrees. These temperature-dependent transitions were paralleled by progressive changes in sedimentation velocities from s20, w of 10.4 at 25 degrees to 7.3 at 10 degrees as measured by active band centrifugation. The linear Arrhenius plot for apparent V max and the constancy of S0.5 for the substrate manganous isocitrate between 35 and 5 degrees suggest that this temperature-dependent conformational change may not be solely related to manganous isocitrate. Further indications of equilibria between different species of enzyme in solution and effects of substrates and cofactors on conformation came from studies of specific activity of enzyme diluted into buffers at 3 and 25 degrees. Dilution to concentrations between 10 and 25 mum enzyme resulted in relatively rapid protein concentration-dependent inactivation which could be prevented and fully reversed by manganous isocitrate. No further substantial inactivation was found subsequent to this phase at 25 degrees. Lowering the temperature of the dilution buffer to 3 degrees favored formation of enzyme species exhibiting a further time and pH-dependent loss of activity which became independent of protein concentration below 7 mum enzyme. The rate of cold inactivation was reduced by raising the ionic strength of the buffer and its progress could be arrested by manganous isocitrate; however, the substrate did not restore the original activity.

Animals↗

PubMed1975

Myelographic cervical nerve root deformities.

Myelograms of nerve roots and adjacent subarachnoid space were reviewed to characterize 231 cervical root deformities from both symptomatic and asymptomatic patients. Good correlation between specific features of root deformities and clinical significance could not be demonstrated. Some features were slightly suggestive of clinical significance but occurred in a sufficient number of asymptomatic patients to make them unreliable. The most accurate determinants of root deformity significance are clincal and electromyographic findings.

Adult↗

PubMed1974