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Biomedical subjects

M G Straatmann

Publications and source records attributed to M G Straatmann.

6 recordsLinked to original sources
PubMed1977

Carbon-11-labeled methylated polyamine analogs: uptake in prostate and tumor in animal models.

The polyamines putrescine, spermine, and spermidine were methylated by the addition of carbon-11-labeled formaledehyde followed by sodium borohydride. High labeling yields wrbon-11-labeled formaldehyde followed by sodium borohydride. High labeling yields were obtained and the final products were purified by simply boiling the solution. This decomposed the excess sodium borohydride and removed the volatile impurities. The final radiochemical purity of all the methylated compounds was above 85%. All three methyltated compounds accumulated in the prostates of male rats and the distribution of N-methyl-1,4-diaminobutane (the putrescine analog) was very similar to that previously obtained with tritiated putrescine. The uptake of the putrescine analog in both the prostate and in mouse tumor was slightly higher than that obtained with the other two analogs studied. Utilizing a positron transaxial tomographic scanner and the putrescine analog, we have been able to image the prostate gland of a dog.

Animals↗
PubMed1977

Fluorine-18-labeled diethylaminosulfur trifluoride (DAST): an F-for-OH fluorinating agent.

A new fluorinating agent was developed by incorporation of 18F into diethylaminosulfur trifluoride (DAST), a reagent capable of replacing hydroxyl and carbonyl oxygen with fluorine. The DAST was synthesized using sulfur tetrafluoride and trimethylsilyldiethylamine in a freon-11 solvent at -78 degrees C and purified by reduced-pressure distillation. Labeling was then accomplished by exchange with anhydrous 18F-hydrofluoric acid, which caused more than 80% of the available activity to be incorporated into the DAST. Fluorine-18-labeled methyl fluoride, ethyl fluoride, and 2-fluoroethanol were prepared from methanol, ethanol, and ethylene glycol, with yields of 20%, 25%, and 12%, respectively.

Ethanol↗
PubMed1976

Blood-brain barrier permeability of 11C-labeled alcohols and 15O-labeled water.

The extraction of 11C-labeled methanol, ethanol, and isopropanol, as well as 15O-labeled water by the brain during a single capillary transit, was studied in vivo in six adult rhesus monkeys by external detection of the time course of these tracers subsequent to their internal carotid artery injection. The data demonstrate the feasibility of accurately measuring brain permeability of highly diffusible substances by this technique and show that neither water nor the alcohols studied freely equilibrate with brain when the cerebral blood flow exceeds 30 ml/100 g min-1. At a cerebral blood flow of 50 ml/100 g min-1 only about 93% of an injected bolus of labeled water freely exchanges with brain, compared with methanol (93%), ethanol (97%), and isopropanol (99%). The brain capillary permeability-surface area (PS) products computed from these data were 0.023 cm3/s g-1 (water), 0.024 cm3/s g-1 (methanol), 0.030 cm3/s g-1 (ethanol), and 0.062 cm3/s g-1 (isopropanol). This sequence of PS products is consistent with the individual lipid solubilities of the alcohols studied and underscores the unique brain permeability characteristics of lipid-insoluble water.

Alcohols↗
PubMed1975

A general method for labeling proteins with 11C.

A method for labeling proteins with 11C has been developed. The method consists of adding 11C-formaldehyde (derived from 11CO2 by catalytic oxidation of 11C-methanol) to a buffered protein solution, followed by reduction of the resulting formaldehyde-protein adduct with aliquots of sodium borohydride. Separation of the desired product is achieved simply and efficiently using high-speed liquid chromatography or, in the case of fibrinogen, by ammonium sulfate precipitation. This mild technique leads to high yields of labeled protein and is adaptable to the labeling of proteins and peptides or other molecules which contain a free amino group and which are stable at pH 8.

Albumins↗