Search PubMedSearch

Biomedical subjects

L Sperling

Publications and source records attributed to L Sperling.

10 recordsLinked to original sources

Pterin-6-aldehyde, a cancer cell catabolite: identification and application in diagnosis and treatment of human cancer.

Active folic acid degradation with the formation pterin-6-aldehyde is a previously undescribed characteristic of cancer cells in tissue culture. Neither normal adult epithelial and fibroblastic cells nor human amniotic cells nor mouse embryonic fibroblasts degrade folic acid to a measurable degree. Twenty-nine patients whose diagnoses were not revealed until after the test of their first morning urine for pterin-6-aldehyde was completed were studied for the presence or absence of pterin-6-aldehyde by thin-layer chromatography. Pterin-6-aldehyde was found in the urine at about 300 nmol/ml or greater only in those 13 patients with a tissue diagnosis of cancer. When the cancer was totally resected, the pterin-6-aldehyde was no longer found in the urine postoperatively. Pterin-6-aldehyde is not found in the urine of healthy patients at this level of detection unless their diets are supplemented with folic acid.

Adolescent

The grip pattern of the healthy hand during eating.

Thirty subjects with healthy hands have been studied in standardized meal experiments comprising serving, eating and drinking. The activities were filmed and the grips classified by means of a descriptive code system and analysed by automatic data processing. The investigation has resulted in new information about the grip pattern of the normal hand as well as detailed data on fingers and parts of fingers used. The study demonstrates the value of analysing hand function with reference to integrated activities.

Activities of Daily Living

Grip function of the healthy hand in a standardized hand function test. A study of the Rancho Los Amigos test.

In an experimental study 30 healthy subjects performed the tests of prehensile function in the Rancho Los Amigos test. The subjects were allowed a free choice of grip instead of those prescribed when the test is used for clinical purposes. The hand-grips were filmed and registered by means of a descriptive code system and the results were subjected to automatic data processing. The results showed that healthy subjects performing the RLA test used a stereo-typed grip pattern as a consequence of the uniform purpose of the hand-grips. Comparison with the results from a standardized meal study in the same subjects showed that functional assessment of a patient with a test of this type is not directly applicable to integrated daily activities, as several of the hand-grips most frequent in daily activities were rarely used. Comparison with types of grip prescribed for clinical use of the test showed that normal subjects often did not spontaneously handle the objects in the manner intended by the test.

Activities of Daily Living

Squid retinochrome.

Retinochrome is a photosensitive pigment located primarily in the inner portions of the visual cells of cephalopods. Its absorption spectrum resembles that of rhodopsin, but its chromophore is all-trans retinal, which light isomerizes to 11-cis, the reverse of the situation in rhodopsin. The 11-cis photoproduct of retinochrome slowly reverts to retinochrome in the dark. The chromophoric site of retinochrome is more reactive than that of most visual pigments: (a) Hydroxylamine converts retinochrome in the dark to all-trans retinal oxime + retinochrome opsin. (by Sodium borohydride reduces it to N-retinyl opsin. (c) Lambda max of retinochrome shifts from 500 to 515 nm as the pH is raised from 6 to 10, with a loss of absorption above pH 8; meanwhile above this PH a second band appears at shorter wavelengths with lambda max 375 nm. These changes are reversible. (d) If retinochrome is incubated with all-trans 3-dehydroretinal (retinal2) in the dark, some 3-dehydroretinochrome (retinochrome2, lambda max about 515 nm) is formed. Conversely, when retinochrome2, made by adding all-trans retinal2 to bleached retinochrome or retinochrome opsin, is incubated in the dark with all-trans retinal some of it is converted to retinochrome. Retinal and 3-dehydroretinal therefore can replace each other as chromophores in the dark.

Borohydrides