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Biomedical subjects

R E Zimmerman

Publications and source records attributed to R E Zimmerman.

At least 37 records · Page 2Linked to original sources
PubMed1984

An intravaginal contraceptive device for the delivery of an acrosin and hyaluronidase inhibitor.

A study was begun to develop a contraceptive delivery system that would free the user from precoital or daily administration and utilize a nonhormonal agent as the active ingredient. Testing of such a system in rabbits has led to the development of a device that will release a controlled level of an acrosin and hyaluronidase inhibitor into the vagina. This toroidal device is composed of a core of tetradecyl sodium sulfate (TDSS) incorporated in polyurethane surrounded by a rate-limiting membrane of polyurethane. Such devices had a sustained in vitro TDSS release rate of greater than or equal to 400 micrograms/day for over 30 days. These devices had a complete contraceptive effect in 15 rabbits bred weekly for 4 weeks. The contraceptive effect is due to release of the TDSS into the vagina and the subsequent binding of the TDSS to spermatozoa in the female reproductive tract. TDSS has a very low toxicity profile in the rat, dog, and rabbit.

Acrosin↗
PubMed1984

Improved performance from modifications to the multidetector SPECT brain scanner.

A multidetector single photon emission computerized tomographic brain scanner was modified to improve the angular sampling. The detector plate was rotated such that 12, 24, or 36 angular projections could be acquired. Phantom experiments demonstrated that the angular aliasing artifacts seen in images obtained with 12 detectors were eliminated with 36 effective detectors. In addition, the reconstructed image noise in a uniform source was decreased by a factor of 1.7 by the use of 36 instead of 12 angular projections, as predicted by computer simulation.

Brain↗
PubMed1983

Antifertility effects of tetradecyl sodium sulphate in rabbits.

Acrosin and acrosomal hyaluronidase were inhibited by tetradecyl sodium sulphate (TDSS) in vitro at concentrations of less than 10(-4) M. TDSS prevented the removal in vitro of the cumulus oophorus by testicular hyaluronidase and the zona pellucida by acrosin. TDSS had a contraceptive effect in rabbits when administered intravaginally before coitus or released at levels of 1-3 micrograms/day from intrauterine silicone rubber devices.

Acrosin↗
PubMed1983

Biodistribution and dosimetry of N-isopropyl-p-[123I]iodoamphetamine in the primate.

The biodistribution of N-isopropyl-p-[123I]iodoamphetamine (I-123 IMP) in the Macaca fascicularis monkey was determined at 15 min and at 1, 4, 24, and 48 hr after intravenous injection. Brain uptake was 7.8% of the injected dose at 1 hr, with little change in concentration between 15 min and 1 hr, falling thereafter. Eye uptake reached a maximum of 0.23% of injected dose at 24 hr, with activity primarily in the pigmented layers. The human absorbed radiation dose was calculated on the basis of biodistribution data. The critical organ is the eye (0.407 rad/mCi of I-123 IMP). The eye dose increased to 1.11 rad/mCi with 4% contamination from I-124 IMP and to 0.535 rad/mCi with 0.4% contamination from I-125 IMP. The absorbed dose to the liver was 0.127 rad/mCi for pure I-123 IMP and the thyroid dose was 0.120 rad/mCi, both increasing with either I-124 or I-125 contamination. While delayed eye uptake has not yet been reported in the human, care should be exercised in limiting the amount of contaminating I-124 or I-125 to the lowest practical level.

Absorption↗
PubMed1982

Utilization of parasternal lymphoscintigraphy in radiation therapy of breast carcinoma.

In radiation therapy of patients with breast carcinoma, the ipsilateral internal mammary lymph nodes are either irradiated by a separate anterior field or included by isocentric opposing tangential fields, which also treat the breast and chest wall. To determine the acceptability of a particular treatment setup, the positions of the nodes must be determined with respect to the treatment fields. For the anterior field technique the problem is two-dimensional and is solved by simply superimposing the treatment field onto an anterior lymphoscintigram. For treatment by opposing tangential fields the problem is three-dimensional and more complex. The solution described in this note is to project the three-dimensional lymph node positions, obtained by a stereo-lymphoscintigraphic procedure, onto the tangential field radiographs. A mathematical expression is given to perform the required projection of the node positions onto the radiographs.

Breast Neoplasms↗
PubMed1982

Initial experience with SPECT (single-photon computerized tomography) of the brain using N-isopropyl I-123 p-iodoamphetamine: concise communication.

Forty-six patients were studied with N-isopropyl I-123 p-iodoamphetamine (IMP) and the Harvard Scanning Multidetector Brain System. In nine control patients, good differentiation between the gray and white matter of the cerebral cortex and the basal ganglia was evident. Regional uptake was affected by physiologic maneuvers (visual stimulation). In 24 patients studied for stroke, IMP images demonstrated areas that were involved in acute infarction in eight patients whose initial transmission computerized tomography (TCT) was normal; IMP also showed perfusion abnormalities larger than the TCT abnormality in ten patients. Perfusion abnormalities were present in 23/24 of these patients. Seven patients studied with a history of TIA had normal TCT and IMP images. In three patients studied during seizure activity, regions of hyperperfusion corresponded to the EEG seizure focus. Markedly decreased activity was present in three patients with brain tumor and corresponded to the focal abnormality on the TCT study. Our study demonstrates the feasibility of assessing regional brain perfusion using a radiopharmaceutical that is lipid soluble and has a high extraction fraction in the brain, together with single-photon ECT.

Amphetamines↗
PubMed1981

Therapeutic intraperitoneal 32P: a clinical assessment of the dynamics of distribution.

With an Anger camera for scintigraphic recording of bremsstrahlung radiation from phosphorus-32, the distribution of intraperitoneal colloidal chromic phosphate was followed in patients with gynecologic tumors. Sequential pelvic, abdominal, and thoracic scintiphotos over a three-week period revealed rapid and persistent focal aggregation of the radiocolloid with no change in pelvic or peritoneal radionuclide distribution patterns. Visualization of intrathoracic lymph node uptake did not correlate with the presence of diaphragmatic tumor. This study demonstrates the utility of scintigraphy for monitoring the distribution of intraperitoneal beta emitters and the need for developing alternative methods of administering these therapeutic agents to achieve more uniform patterns of distribution.

Brachytherapy↗
PubMed1981

Characteristics of a scanning, multidetector, single-photon ECT body imager.

We evaluated a single-photon emission computed tomographic system using ten scanning detectors in a circular array. The system uses focusing collimators that scan radially as well as tangentially. The spatial resolution in the tomographic plane is 2.6 cm FWHM and the axial resolution is 3.3 cm FWHM. The resolution is independent of position within the field of view, and nearly independent of energy through 511 keV. Sensitivity was found to be 4600 cps/muCi-ml for an extended phantom, 20-cm in diameter, filled with Tc-99m; 7200 cps/muCi-ml with TI-201; and 8000 cps/muCi-ml with Ga-67. Investigations of positional uniformity indicated some quantitative distortion of data due to inadequate attenuation correction. Improvement in the attenuation correction is necessary before truly quantitative tracer distribution studies are undertaken.

Evaluation Studies as Topic↗
PubMed1980

An industrial hygiene evaluation of chimney sweeping.

With the increased use of wood and coal for home heating, chimney sweeping is becoming a more common occupation. A preliminary study was designed to evaluate the air contaminants present in the process. Arsenic and sulfur dioxide were found along with coal tar pitch volatiles. A method of minimizing the exposure of these chemicals to chimney sweeps by spraying a water mist is discussed.

Air Pollutants↗
PubMed1980

Double-tracer, multiple-organ transaxial emission computed tomography: improved localization and characterization of radiotracer distributions.

Transaxial emission computed tomography (ECT) was performed in dogs with experimentally induced abscesses, using 67Ga and several 99mTc-labeled organ-specific radiopharmaceuticals. Superimposition of 99mTc ECT images onto the 67Ga images gave the precise anatomic location of the abnormal foci of 67Ga uptake, correctly localizing a perinephric abscess, a splenic abscess, and a focus of osteomyelitis. This technique also permits further characterization of regions of decreased activity.

Abscess↗
PubMed1980

The inhibition of acrosin by sterol sulphates.

Four 3 beta-hydroxy-delta 5-steroid sulphates were found to be potent and specific inhibitors of the sperm acrosomal proteinase, acrosin. Two of these acrosin inhibitors, desmosteryl sulphate and cholesteryl sulphate, occur naturally in spermatozoa. Desmosteryl sulphate, an inhibitor of the in-vitro capacitation of hamster spermatozoa, has a Ki of 3.5 x 10(-6) M for the inhibition of acrosin. The mechanism of inhibition of sperm capacitation by sterol sulphates is probably due to their inhibition of acrosin.

Acrosin↗
PubMed1979

Single-photon transaxial emission computed tomography of the heart in normal subjects and in patients with infarction.

Resting computerized transaxial tomography was performed after the i.v. injection of thallium-201 in six normal subjects and in five patients who had had myocardial infarctions 3 mo to 4 yr before scintigraphy. Decreased myocardial activity corresponded to the site of previous infarction in all cases and was clearly separated from adjacent myocardium with normal activity. With tomography, the left ventricle was clearly separated from surrounding structures such as the left-ventricular cavity, the lungs, and the liver. This study demonstrates the feasibility for the assessment of myocardial perfusion using single-photon transaxial emmission computed tomography.

Heart↗
PubMed1979

Tantalum-178-labeled agents for lung and liver imaging.

Despite its 9.3-min half-life, Ta-178 can be used to produce radiopharmaceuticals for lung and liver imaging. A variety of human serum albumin microspheres and other particulate radiopharmaceuticals were labeled with Ta-178. A period of approximately 10 min was required for their preparation and administration to rats. Extrapolation to the clinical situation suggests that imaging could take place after one half-life of the nuclide has elapsed. We found that satisfactory imaging is possible using Ta-178 radiopharmaceuticals with the Anger camera and a pinhole collimator. Since short imaging times, high spatial resolution, and low patient doses are reasonable objectives in pediatric scintigraphy, these new radiotracers may prove useful for lung and liver imaging in children.

Animals↗
PubMed1979

Scintigraphic imaging with tantalum-178 and the Anger scintillation camera: concise communication.

Tantalum-178 is a short-liver radionuclide (T 1/2 = 9.3 min.) and emits primarily 56- to 64-keV characteristic x-rays. We have determined the imaging characteristics with this radionuclide and a large-field-of-view Anger camera. With a pinhole collimator, good spatial resolution is possible with Ta-178, although the image quality is superior with Tc-99m under comparable conditions. Spatial resolution with parallel-hole or converging collimators was much less satisfactory with Ta-178 because of septal penetration by high-energy photons. Pulmonary perfusion and liver-spleen images of excellent quality were obtained in the rabbit using the pinhole collimator and Ta-178-labeled agents.

Animals↗