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Biomedical subjects

R W Grant

Publications and source records attributed to R W Grant.

28 records · Page 2Linked to original sources
PubMed1976

Increased rate of disappearance of serum probenecid in barbital dependent rats.

Rats were made barbital dependent by administration of barbital in their drinking water. Subsequently, the rats were either not withdrawn (BN) or withdrawn from barbital for 24 h (BW-24). Before sacrifice, probenecid was administered to measure brain serotonin turnover. A statistically significant decrease in 5-hydroxyindoleacetic acid (5-HIAA) accumulation was observed in the cerebral cortex medulla pons and midbrain. Subsequentialy, serum levels of probenecid were also measured by gas chromatography to determine if chronic barbital consumption might affect circulating probenecid. By ninety minutes following probenecid administration, serum probenecid levels in BN and BW-24 rats were significantly lower than control while a probenecid metabolite was significantly increased. The significantly reduced accumulation of 5-HIAA in brain areas of BN and BW-24 rats is probably the result of the more rapid decline of probenecid rather than a true decrease in serotonin turnover.

Animals↗
PubMed1975

Quantitative liver imaging using 131-I Rose Bengal as an index of liver function and prognosis.

A technique for assessing quantitatively hepatic function by direct measurement of liver parenchymal cell uptake of 131I Rose Bengal using a scintillation camera with a digital store and retrieval system is described. Ninety-four studies were performed on 84 patients with a variety of hepatic disorders over a two-year period, the diagnosis in each case being established by liver biopsy or laparotomy. The results were compared with the clinical, biochemical and histological assessment of the patients. A good correlation was found between the half-time for hepatic uptake of 131I Rose Bengal and the histological changes, as well as with clinical prognosis measured in terms of clinical improvement or deterioration to death. The rate of liver uptake was found to be a better index than the clearance of radioisotope from the blood and was superior to conventional biochemical investigations in both icteric and anicteric patients. The test was not shown to be of clinical value in discriminating between intra- and extrahepatic causes of jaundice. It is suggested that this technique may provide a safe and sensitive method for assessing the severity of liver dysfunction and also for monitoring clinical progress, especially in situations where liver biopsy may be unreliable or hazardous.

Biopsy↗
PubMed1975

Deconvolution analysis of the scintillation camera renogram.

A scintillation camera with digital data store has been used to assess renal function. Analysis of the renogram by deconvolution, using an on-line digital computer, shows promise as a means of expressing renal function in terms of tubular transit times for 123I-Hippuran.

Computers↗
PubMed1969

A comparison of the iron bonding in anhydrohemoglobin and anhydromyoglobin.

Mössbauer effect measurements show that the ferrous ions in dehydrated deoxymyoglobin are in the high spin state while those in dehydrated deoxyhemoglobin (AHb) are equally distributed between high and low spin states. It is concluded that the two spin states present in AHb are associated with the iron site difference of the alpha- and beta-chains.

Hemoglobins↗
PubMed1965

Mössbauer effect in hemoglobin and some iron-containing biological compounds.

The Mössbauer effect in Fe(57) has been used to study the molecules, hemoglobin, O(2)-hemoglobin, CO(2)-hemoglobin, and CO-hemoglobin (within red cells) and the molecules, hemin and hematin (in the crystalline state). Quadrupole splittings and isomeric shifts observed in the Mössbauer spectra of these molecules are tabulated. The temperature dependence of the quadrupole splitting and relative recoil-free fraction for hemoglobin with different ligands has been investigated. An estimate of the Debye-Waller factor in O(2)-hemoglobin at 5 degrees K is 0.83. An asymmetry in the quadrupole splitting observed in hemoglobin is attributed to a directional dependence of the recoil-free fraction which establishes the sign of the electric field gradient in the molecule and indicates that the lowest lying d orbital of the Fe atoms is |xy>. This asymmetry indicates that the iron atoms in hemoglobin are vibrating farther perpendicular to the heme planes than parallel to them, and, in fact, the ratio of the mean square displacements perpendicular and parallel to the heme planes in hemoglobin is approximately 5.5 at 5 degrees K. The temperature dependence of the quadrupole splitting in hemoglobin has been used to estimate a splitting between the lowest lying iron atom d orbitals of approximately 420 cm(-1).

Carbon Dioxide↗