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Biomedical subjects

V Levin

Publications and source records attributed to V Levin.

44 records · Page 3Linked to original sources
PubMed1978

Quantitative aspects of contrast enhancement in cranial computed tomography.

The temporal relationship of blood iodine levels to tumor enhancement in cranial computed tomography was studied in a series of patients. Both the bolus and biphasic techniques were evaluated. Peak tumor intensity may not develop immediately, but may be more pronounced on a 20-minute scan. The low-density centers seen in malignant gliomas show delayed enhancement. These low-density centers represent a second compartment which equilibrates with the intravascular and interstitial contrast material at a much slower rate. Patients with malignant gliomas can be scanned up to one hour following contrast injection without significant loss of information.

Blood-Brain Barrier↗
PubMed1977

Brain tumors: criteria of response and definition of recurrence.

The criteria for determining response to therapy and establishing brain tumor recurrence are presented. Basing their conclusions on a series of more than 500 patients, the authors contend that serial scintiscans and computerized axial tomograms can be used to determine accurately the response to therapy and recurrence or tumor regrowth. The problems in evaluating response and tumor recurrence are discussed, with emphasis on those relating to concurrent glucocorticoid therapy and medical conditions such as infection, hematomas, and drug side-effects.

Antineoplastic Agents↗
PubMed1975

Phase II study of procarbazine, CCNU, and vincristine combination chemotherapy in the treatment of malignant brain tumors.

Forty-eight patients with primary or metastatic malignant tumors of the central nervous system (CNS) were treated with combination chemotherapy, consisting or procarbazine (100 mg/m2 X 14 days), CCNU (75 mg/m2), and vincristine (1.4 mg/m2 X 2, 1 week apart) (PCV) every 4 weeks. Most patients had undergone initial resection of primary tumors, postoperative radiotherapy, and a post irradiation interval of 3 months or more. Other patients harbored unbiopsied, newly-discovered primary or metastatic tumors. All patients were deteriorating neurologically when treatment began. Overall response rate for PCV combination therapy was 44%, no better than results obtained with single agent procarbazine or BCNU, the most effective drugs used alone in previous brain tumor chemotherapy studies.

Brain Neoplasms↗
PubMed1972

A compartmental analysis of 24 Na kinetics in rat cerebrum, sciatic nerve and cerebrospinal fluid.

1. The kinetics of (24)Na exchange in rat cerebrospinal fluid, brain and sciatic nerve were studied during steady-state plasma isotope conditions. The entrance of (24)Na into brain and sciatic nerve was found to fit a three compartmental model. Using newly derived equations for compartmental analysis, the first compartment (24)Na space of brain was found to be about 22% and the second compartment space about 6%; the corresponding sciatic nerve spaces were 26 and 11%, respectively. In the discussion, arguments are presented that suggest that the first compartment is the extracellular space (ECS) and the second compartment is the intracellular space. The t((1/2)) for compartmental equilibration between plasma and brain ECS was 2 hr and from ECS to intracellular space 14 hr; in nerve the respective t((1/2))'s were (2/3) hr and 10 hr.2. A third compartment of 18% was found in sciatic nerve which was interpreted to be anatomically confined to the epi- and perineurium; in brain the corresponding space was 2% and was felt to be anatomically and kinetically an inactive closed compartment in parallel with the blood.3. There were two t((1/2))'s for plasma-c.s.f. (24)Na equilibration of less than 10 min and 2 hr.4. Profiles of brain, from cortex to ventricle, at 6 min, demonstrated a gradient of decreasing (24)Na radioactivity from ventricle to cortex.

Animals↗