Search PubMed⌕ Search

Biomedical subjects

G Levine

Publications and source records attributed to G Levine.

At least 55 records · Page 3Linked to original sources
PubMed1986

Tumor location and drug targeting using a monoclonal antibody (anti-SSEA-1) and antigen-binding fragments.

Both murine and heterotransplanted human nonseminomatous germ-cell tumors have been successfully located by external scintigraphy using radioiodinated anti-SSEA-1, a monoclonal IgM, and its pepsin-derived antigen-binding fragment, F(ab')2 mu. Antibody localization in the tumor is mainly due to antigenic specificity, rather than to nonspecific trapping, and depends strongly on the amount of time after injection. The antibody has been used for drug targeting in vitro and in vivo.

Animals↗
PubMed1985

Stereotactic intracavitary irradiation of cystic neoplasms of the brain.

Ten patients with intracranial cystic tumors underwent stereotactic intracavitary irradiation using 32P colloidal chromic phosphate. Accurate dosimetry (25,000-30,000 rad to the cast wall) was achieved by volume estimation using computed tomography. Between 1 and 15 months after surgery both craniopharyngioma and astrocytoma cysts regressed. Neurological, visual, and endocrinological deficits either stabilized or improved. Intracavitary irradiation should be the primary method of treating solitary cystic tumors of the brain.

Adolescent↗
PubMed1985

Involvement of Golgi apparatus and a restructured nuclear envelope during biogenesis and transport of herpes simplex virus glycoproteins.

Following infection of BHK-21 cells with Herpes simplex virus type 1 (HSV-1), progeny nucleocapsids in the nucleus acquire a glycoprotein-rich envelope by budding through host-cell nuclear membranes. To investigate the nature of the glycoprotein products assembled in the virion at the nuclear envelope, infected cells were pulse-labeled with [3H]-mannose, an oligosaccharidal core sugar, or [3H]-fucose, a terminal sugar. After various chase periods, the incorporation of these sugars was monitored by electron microscope radioautography. The results show that HSV glycoproteins accumulate very rapidly in nuclear membranes, where they exist only as core-glycosylated precursors, i.e., containing [3H]-mannose but not [3H]-fucose. [3H]-fucose grains are seen mainly over Golgi membranes and over virions located in the Golgi and in other cytoplasmic vesicular structures. Our data support a model where addition of terminal sugars (e.g., fucose) to HSV-1 glycoprotein precursors can occur at the surface of newly enveloped viral particles as the virions themselves egress from the cell via the Golgi apparatus.

Animals↗
PubMed1985

Comparison of computerized tomographic and radionuclide methods in determining intracranial cystic tumor volumes.

The dosimetry of radioactive phosphorus (32P) for intracavitary treatment of cystic brain tumors is dependent upon accurate determination of the cyst volume. The authors have used both high-resolution computerized tomography (CT) scanning and an isotope dilution technique with technetium-99m (99mTc) sulfur colloid to determine cyst volumes in an experimental model and in six patients with intracerebral cystic tumors. In six separate comparisons using an experimental phantom "cyst," no significant differences between CT and 99mTc values were detected. In six patients with cystic neoplasms varying from 3 to 6.7 ml in volume, the percent differences between values obtained by CT and isotope dilution ranged from -17.26% to +13.13%. In individual patients, these differences proved to be of little significance for planning dosimetry. In both experimental and clinical trials comparing isotope dilution and CT measurement techniques, the CT technique using the standard software of the scanner and 5-mm thick slices proved to be a highly accurate method of determining cyst volume. The authors now base dosimetric calculations for intracavitary radiation with 32P on CT technique alone.

Astrocytoma↗
PubMed1985

Tumor location using F(ab')2 mu from a monoclonal IgM antibody: pharmacokinetics.

A monoclonal IgM antibody (anti-SSEA-1) and its divalent antigen-binding peptic fragment [F(ab')2 mu] were compared as in vivo tumor localization reagents in mouse teratocarcinomas. F(ab')2 mu is cleared more rapidly than whole antibody from the whole body, blood, and all tested organs (t1/2 for whole antibody approximately 18 hr; t1/2 for F(ab')2 mu, 12 hr). A corresponding average improvement in tumor-to-tissue ratio is observed 48 hr after injection and earlier. However, the affinity of the F(ab')2 mu for antigen is much lower, and a smaller fraction of the antibody fragment is retained in the tumor than with whole antibody. The fragment was not retained by animals bearing nonantigenic tumors.

Animals↗
PubMed1982

Intracellular transport of the transmembrane glycoprotein G of vesicular stomatitis virus through the Golgi apparatus as visualized by electron microscope radioautography.

The intracellular migration of G protein in vesicular stomatitis virus-infected cells was visualized by light and electron microscope radioautography after a 2-min pulse with [3H]mannose followed by nonradioactive chase for various intervals. The radioactivity initially (at 5-10 min) appeared predominantly in the endoplasmic reticulum, and the [3H]mannose-labeled G protein produced was sensitive to endoglycosidase H. Silver grains were subsequently (at 30-40 min) observed over the Golgi apparatus, and the [3H]mannose-labeled G protein became resistant to endoglycosidase H digestion. Our data directly demonstrate the intracellular transport of a plasmalemma-destined transmembrane glycoprotein through the Golgi apparatus.

Animals↗
PubMed1982

Tumor immunity in rat lymph nodes following transplantation.

Inguinal lymph nodes in the Buffalo rat were autotransplanted to the popliteal fossa by an intact vascular pedicle or by microvascular anastomosis. These revascularized nodes had normal histology and made spontaneous afferent and efferent lymphatic reconnection with surrounding lymphatic vessels, as documented by ink and silicone rubber injection studies. Lymphoscintigraphy with 99mTc antimony sulfide colloid correctly predicted the 44 of 120 node transplants that had made afferent reconnection. To demonstrate immunologic activity of lymph nodes following transplantation, a cellular adherance assay was employed to detect cell-mediated cytotoxicity of lymph node cells isolated from rats sensitized to an allogeneic gliosarcoma. Cytotoxicity was detected in nontransplanted regional nodes sensitized to tumor (p less than 0.01) and in nodes transplanted by vascular pedicle and then sensitized to tumor (p less than 0.001). This study demonstrates that lymph nodes can be transplanted with restoration of functional lymphatic anatomy, and that following transplantation, lymph nodes retain the ability to mount an immune response against tumor.

Animals↗
PubMed1982

Protein adsorption in vitro onto biomaterial surfaces covered with ULTI carbon.

A study is presented which describes the adsorption in vitro of albumin and fibrinogen onto a mini-shunt oxygenation unit. The unit is characterized by flow through 10 etched microchannel conduits with a microporous membrane and conduits are pretreated with a uniform layer of ULTI carbon and evaluated for the steady-state and time varying kinetics of protein adsorption. Corresponding results for oxygenator components not pretreated with ULTI carbon are also included.

Adsorption↗
PubMed1980

Influence of dimercaprol (2,3-dimercapto-1-propanol) on the pharmacokinetics of 111In-bleomycin in the P-1798 lymphoma-bearing BALB/c mouse.

The pharmacokinetics of 111 indium-labeled bleomycin were altered in the P-1798 tumor-bearing BALB/c mouse when pretreated with the dithiol 2,3-dimercapto-1-propanol (Bal). 1 mg of BAL administered 1 h prior to 20 microCi of 111In-bleomycin resulted in 2:1 tumor loading and 3:1 liver loading of 111In-bleomycin over controls (p less than or equal to 0.05 at the 2- to 3-hour interval). Muscle uptake during this interval remained at unity.

Animals↗
PubMed1980

Localization of I-131-labeled tumor-specific monoclonal antibody in the tumor-bearing BALB/c mouse.

One of the most frequent indications for patient imaging is the need to establish the presence or absence of malignant disease. Considerable effort has been invested in attempting to develop tumor-specific radiopharmaceuticals. We report the localization of an iodine-131-labeled, hybridoma-derived monoclonal antibody in the MH-15 teratocarcinoma-bearing BALB/c mouse. Tumor-to-muscle and tumor-to-blood ratios of 150:1 and 15:1, respectively, were observed at 5 days after administration of 15 microCi of labeled antibody. The relationship between the optimal imaging time and localization kinetics is discussed.

Animals↗
PubMed1979

Coagulation studies of patients taking low-dose heparin during and after major gynecologic surgery.

In February, 1975, a prospective, randomized study of 75 patients undergoing major gynecologic surgery was undertaken. Patients were randomly assigned to three groups regardless of diagnosis and surgery contemplated. Coagulation studies were performed preoperatively and postoperatively in a control group, a receiving 2,000 U heparin/12 hr subcutaneously, and a third group receiving 5,000 U/12 hr via the same route. There was a statistically significant increase noted in fibrin degradation products in the group treated with 5,000 U heparin/12 hr as compared to the control group. Excessive bleeding intraoperatively or postoperatively was not encountered.

Antifibrinolytic Agents↗
PubMed1979

Radiopharmacist profile--baseline 1974-1975.

The results of a baseline October 1974 to March 1975 survey are analyzed to describe what constitutes radiopharmacists' education, training, and professional practice. Frequency distributions for the following descriptors are presented: age, location, highest degree earned, major radiopharmaceutical training, years of experience, time devoted to radiopharmacy, principal place of work, salary, and major appointment or responsibility. Preliminary examination of the possible association of some of these descriptors is made; a radiopharmacist profile is presented.

Education, Pharmacy↗