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Biomedical subjects

H L Cox

Publications and source records attributed to H L Cox.

13 recordsLinked to original sources
PubMed1980

CT for intracavitary radiotherapy planning.

Twenty-two patients with malignant uterine tumors were examined with computed tomography (CT) for treatment planning after insertion of an afterloading Fletcher applicator. The CT findings maximized the individualization of treatment planning, including the number, dosage, and loading arrangement of radioactive sources. Artifacts were produced by the metal; but in most cases the scans accurately portrayed the three-dimensional anatomic relationship of the applicator, uterus, and neighboring vital structures. The CT information made it possible to calculate dose distribution more rapidly and accurately for both intracavitary therapy and combined intracavitary and external therapy. Unsuspected uterine perforation was detected by CT in one case.

Aged↗
PubMed1979

First-pass effect after rectal administration of thiazinamium methylsulfate.

The absorption and metabolism of the quaternary ammonium compound thiazinamium methylsulfate were studied in humans using plasma concentration data and urinary excretion measurements. After giving a dose of 150 mg in suppositories, the relative bioavailability was 5.8 +/- 3.2 (SD) % of the dose, comparable to the values obtained following oral administration. The degree of first-pass effect observed after rectal administration was comparable with that after oral administration.

Aged↗
PubMed1976

A syndrome manifested by brittle hair with morphologic and biochemical abnormalities, developmental delay and normal stature.

We have presented 2 affected sibs-a male and female-with unaffected parents and sib from a small remote northern Mexican village. The syndrome includes mental deficit, brittle hair with decreased cuticular layer and an apparently collapsed cortex. The patients' hair contains decreased sulfur content and increased concentrations of trace elements as determined by x-ray fluorescent spectroscopy. Studies are underway to evaluate other apparently similarly affected children from the village where our family originated.

Body Height↗
PubMedDate not supplied

Line-focusing x-ray monochromator for the analysis of trace elements in biological specimens.

A line-focusing x-ray monochromator has been designed and developed to be used with an energy dispersive detection system for the quantitative analysis of trace elements in biological specimens. This instrument uses a cylindrically curved Johansson-type crystal to monochromatize and focus the excitation radiation into a line 0.5 mm wide and 40 mm long. The excitation radiation chosen for these experiments was Mo Kalpha and the total intensity of the line-focused beam was estimated to be 2 X 10(7) cps. Because of the narrow width and high power density of the excitation between beam, small tissue specimens 1 X 1 X 12 mm in size along with a single strand of hair were analyzed for trace elements from Al through Sr. For the transition elements, concentrations of a few parts per million were easily detected with this analyzer.

Hair↗
PubMedDate not supplied

Sample mass determination using Compton- and total scattered excitation radiation for energy-dispersive x-ray fluorescent analysis of trace elements in soft tissue specimens.

Compton profiles and total scattered intensities have been measured to determine the total sample mass, analyzed by an x-ray probe energy-dispersive analyzer. Under photon excitation, fluorescent x rays are emitted from the trace elements in a biological matrix. From incident radiation, the number of photons which are Commpton and elastically scattered by low-atomic-number elements is directly proportional to the total specimen mass. Tissue specimen masses have been measured from Compton intensities using Zr Kalpha and Ma Kalpha excitation x rays and mass calibration standards based upon carbon scattering. This procedure has been extended to include lower-energy excitation radiation, such as Cu, where the resolution of an energy-dispersion system requires that the total scattered intensity be used to determine the sample mass. Trace element weight-fraction concentrations are determined from this scheme with precisions of 1% in 2%, relying only upon information contained in the energy-dispersive x-ray spectrum. By adjusting for the difference between tissue and corbon scattering the accuracy of the elemental weight-fraction concentrations is brought to within 10% of elemental concentrations measured by atomic absorption spectroscopy, for samples weighing up to 25 mg. In the case of heavier samples, absorption corrections are necessary to achieve this accuracy.

Animals↗