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Biomedical subjects

I Fand

Publications and source records attributed to I Fand.

30 records · Page 2Linked to original sources
PubMed1983

Quantitative autoradiography with radiopharmaceuticals, Part 2: Applications in radiopharmaceutical research: concise communication.

We describe the application of macroautoradiography, a relatively simple, quantifiable method for the evaluation of positron-emitting and gamma-emitting radiopharmaceuticals. We have investigated the response properties of two types of film to positron (F-18) and negatron (C-14) emitters. Variations in the response of film to increasing film-to-source distance are described, along with the effects of different intensifying screens and mounting tape. Digitization of whole-body autoradiograms (WBARG) in small animals was performed by using a videodensitometry system (videocamera interfaced to a computer). Quantitation was derived from analysis of a series of step-wedge standards that covered the range of radioactivities in the sample. By using a close-up lens on the videocamera, a 2- by 2-cm field is digitized as a 128 X 128 array, each pixel representing 156 X 156 micron. The effect of chlorpromazine (CPZ) on glucose metabolism in mice was studied by giving C-14 2DG followed by CPZ and F-18 FDG in the same animal. Muscle activity decreased and brown-fat activity increased. The high spatial resolution of this technique enables quantification in structures as small as the basal ganglia in mice. The use of dual-nuclide ARG permits each animal to be its own control, which greatly increases the utility of this method.

Animals↗
PubMed1982

Chlorpromazine distribution in hamsters and mice bearing transplantable melanoma.

Chlorpromazine (CPZ) distribution was measured in tissues of Syrian golden hamsters bearing Greene melanoma and in BALB/c mice bearing Harding-Passey melanoma. Distribution was evaluated as a function of time (0.5 to 14 days) and as a function of single and multiple doses (up to five) of from 5 to 50 mg CPZ per kg body weight. Routes of administration (i.p., i.v., p.o.) were compared. The physiological behavior of CPZ is of interest as it is used extensively as a tranquilizing drug (Thorazine). Further, since CPZ binds to the pigment melanin, the possibility exists of using CPZ to transport diagnostic or therapeutic agents to melanoma. It was found that, at 2 days postinjection, tumor/tissue concentration ratios exceeded 10 for metabolizing organs, such as liver and 100 for "back-ground" tissues, such as blood and muscle. Absolute concentrations of CPZ in tumor exceeding 100 microgram CPZ per g tumor were obtained with both single and multiple doses. This selective high concentration in tumor would make CPZ an ideal vehicle for the transport of boron to tumor for use in neutron capture therapy via the 10B(n, alpha)7Li reaction.

Animals↗
PubMed1981

Whole-body localization of 14C-tocopheryl acetate in the rat following oral administration.

The whole-body localization of dl-alpha-[3, 4-14C2]-tocopheryl acetate was examined in the rat for intervals ranging between 12-96 hr following administration of a single oral dose. Quantitative evaluation of the macroautoradiograms revealed a rapid removal of 14C-vitamin E equivalents from the blood and gut and their accumulation in body tissues. When the densitometric data were expressed as dpm/mm2, the values for radioactivity uptake by the adrenal cortex were systematically the highest of all tissues examined for all time periods. At 12-96 hr after dosing, high activity was noted in spleen, bone marrow, liver, lymph nodes and fat; moderate activity was observed in myocardium, lung, gastric mucosa, pituitary, blood, hair follicles, Harder's gland and nasal mucosa; low values were found in brain, skeletal muscle and spinal cord. The nearly complete exclusion of radiovitamin E from the brain and its localization to the choroid plexus implied the operation of a blood-brain barrier. Labeled vitamin E uptake in brain, salivary glands and skeletal muscle was essentially linear and increased with time over 12-96 hr. For both early and late sacrifice periods, a differential pattern of 14C-radioactivity uptake was observed with the pituitary, where the pars nervosa exhibited 2.8 times greater activity than the pars distalis. The significance of the findings is discussed in relation to the suggested role of vitamin E in pituitary-adrenal functions, hemopoiesis and oral physiology.

Administration, Oral↗
PubMed1977

Cilioinhibitory effect of phenothiazines in vitro and its antagonism by Ca++.

The inhibition of ciliary beating in vitro by physiologic concentrations of chlorpromazine (CPZ) and prochlorperazine (PCP) was demonstrated in two experimental systems. CPZ had a greater cilioinhibitory effect than PCP on the rotational velocity of tissue explants from the frog palate in amphibian Ringers, and on the frequency of ciliary beating in rat tracheal rings in culture medium. Addition of calcium acetate in equal molarity to CPZ, within a time limit dependent on the drug concentration, reversed this inhibition, while dibutyryl cyclic AMP did not. Simultaneous addition of Ca++ and CPZ slowed down, but did not stop, this ciliostasis, while priming with Ca++ or cyclic AMP prior to drug addition had less of an effect. These data lend support to a prevalent theory that CPZ exerts its actions by displacing calcium ions from membrane sites.

Animals↗
PubMedDate not supplied

Optimization of boron and neutron delivery for neutron capture therapy.

A number of groups in the United States have received funding that will permit evaluation of the clinical efficacy of the neutron capture therapy (NCT) procedure. Various reactors are being modified to allow the construction of an epithermal neutron beam. At the Brookhaven Medical Research Reactor (BMRR), the patient irradiation facility is being modified to produce an optimized epithermal neutron beam. An 80-cm-thick A1-D2O mixture (184 g/cm2, 25% D2O by volume) is being installed in the shutter assembly. One-dimensional calculations indicate that this configuration should provide an epithermal neutron flux density of approximately 1 x 10(9) n/cm2/sec at 3 MW and a concomitant fast neutron dose rate of approximately 2 x 10(-11) rad per epithermal neutron (assuming a homogeneous A1-D2O mixture). The actual geometry will be an inhomogeneous array of D2O and A1 layers producing parameters somewhat less favorable than those listed above; experimental verification is in progress. Significant gains have recently been made in selectively targeting B to melanoma with various melanaffinic compounds, including p-boronophenylalanine, and with boronated porphyrins that may be applicable to a variety of tumors. Neutron capture radiographs have been obtained with the above compounds, and efforts have been made to quantitate boron uptake in growing and quiescent or necrotic regions of tumor via double-labeling techniques obtained with tritiated thymidine. A correlation between therapeutic efficacy and the ability to deliver boron to viable areas of tumor has been observed.

Animals↗