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Biomedical subjects

R R Moore

Publications and source records attributed to R R Moore.

12 recordsLinked to original sources
PubMed1997

Use of urine specific gravity to improve screening for albuminuria.

The albumin to creatinine ratio (ACR) can be used to measure urine albumin excretion rates, but is inconvenient and expensive. More rapid and less expensive screening methods estimate only albumin concentration and are subject to errors caused by variation in urine volume. We examined whether urine specific gravity could be used in place of urine creatinine to correct albumin concentration for differences in urine volume in 50 patients. Urine specific gravity accurately estimated urine creatinine concentration (r = 0.79, P < 0.001). The albumin estimated-creatinine ratio (ACestR) in random spot urine sample correlated with urine albumin excretion measured in a 24-hour urine collection (r = 0.98, P < 0.001), as did the ACR (r = 0.95, P < 0.001). For determining microalbuminuria, the sensitivity (0.88) and specificity (0.93) of the ACestR were similar to those of ACR (0.89 and 0.93, respectively). Unfortunately, the sensitivity (0.63) of the Micral-Test was relatively poor, and was only slightly improved by correcting for urine specific gravity (0.69) in this small sample of patients. Nevertheless, these results suggest that as rapid methods for measuring urine albumin concentration improve, combining them with urine specific gravity might produce a less expensive and more convenient alternative to the ACR.

Adult↗
PubMed1985

Observation of tyrosine-O-phosphate in Drosophila melanogaster larvae by 31P-NMR spectroscopy.

31P-NMR spectra of intact larvae and pupae of Drosophila melanogaster have been obtained at 109.3 MHz. A major resonance in these samples has been identified as tyrosine-O-phosphate. Its chemical shift reflects the hemolymph plasma pH. Upon disruption of the organisms (necessary for chemical analyses of tyrosine-O-phosphate), phosphatases rapidly hydrolyze this phosphate ester, generating inorganic phosphate and free tyrosine.

Animals↗
PubMed1985

Correlation of 19F-NMR spectra of halothane in rat tumor and non-tumor tissues with membrane alterations.

The membrane environments in normal and tumor rat tissue and the effect of hyperthermia thereon are studied with 19F-NMR spectroscopy of the general anesthetic halothane. Normal and tumor cell types are clearly differentiated by the halothane resonance. A hydrophobic environment prominent in tumor tissue is more sensitive to heat treatment than the corresponding environments of normal cells. Studies of extracted lipids suggest that this may be due in part to the considerable difference in lipid temperature response which exists between normal and kidney tumor cells.

Adenocarcinoma↗
PubMed1984

The fluorinated anesthetic halothane as a potential NMR biologic probe.

Fluorinated anesthetics such as halothane preferentially partition into hydrophobic environments such as cell membranes. The 19F-NMR spectrum of halothane in a rat adenocarcinoma (with known altered lipid metabolism and membrane composition) shows an altered chemical shift pattern compared to the anesthetic in normal tissue. In eight tumor samples examined, the 19F-NMR spectra exhibit two distinct resonances, compared to a single resonance observed in normal tissues. This is explained by an enhanced or altered hydrophobic component in the tumor tissue giving rise to two discrete halothane environments. Another fluorinated anesthetic, isoflurane, shows similar behavior in distinguishing normal from diseased tissue. Given the large chemical shift range of fluorine and the inherent sensitivity of this nucleus, 19F-NMR spectra of fluorinated anesthetics can also be used to follow anesthetic degradation by the liver. The ability of fluorinated anesthetics to discriminate tissues and to monitor metabolic processes is potentially useful for in vivo 19F-NMR surface coil and imaging studies.

Adenocarcinoma↗
PubMed1978

Dental implant fixation by electrically mediated process. I. Interfacial strength.

In order to determine the effect of electrical stimulation on canine alveolar bone, porous PMMA dental implants with a solid core (on which a Pt-13% Rh electrode was wound) were implanted in the mesial socket of the canine mandibular fourth premolars bilaterally. The positive electrode was implanted into the distal socket. The power pack was placed over the masseteric fossa. The implants, wires and power packs were all implanted subcutaneously. Each animal had an experimental and control implant. Mechanical push-out samples were prepared by sectioning a 2mm thick section of the mandible with the implant in the middle. The samples were tested immediately and the load-deflection curves were obtained.

Alveolar Process↗
PubMed1978

Dental implant fixation by electrically mediated process. II. Tissue ingrowth.

The effect of electrical stimulation on the interfacial strength of the porous polymethylmethacrylate implant/oral tissue union and the amount of tissue growth was investigated in the fourth premolars of dogs. The study indicates the interfacial strength peaks at about three weeks and decreases thereafter for both control and the stimulated specimens. The stimulated side showed consistently higher strength than its paired control. There was a positive relationship between implant period and amount of tissue in the pores although the latter was not correlated with the interfacial strength. Microradiographs showed a different pattern of new bone formation on the stimulated side when compared to the control. On both sides, bone formation occurred upward from the bottom of the tooth socket while on the stimulated side, new bone also developed from the sides of the tooth socket which was minimal in the controls. It is proposed that the direction of oral tissue formation is responsible for the different results obtained in this study compared with a similar study on long bones.

Animals↗
PubMedDate not supplied

In vivo 19F NMR studies of hyperthermia: hydrophobic environments probed by halothane.

The steady-state distribution of the general anesthetic halothane in different rat tissues, including a renal adenocarcinoma with and without hyperthermia treatment, has been evaluated by in vivo 19F NMR spectroscopy. The 19F spectra of halothane (which is a hydrophobic probe) from within tissue show differences in the partitioning between normal rat tissues and adenocarcinoma. Muscle, as a control tissue, exhibits a single large resonance around 0 ppm. However, the adenocarcinoma exhibits two slow-exchanging resonances separated by 0.3 ppm with the one at the more hydrophobic chemical shift being more sensitive to hyperthermia treatment. The results from this tumor model suggest that 19F NMR spectroscopy may be useful first in detecting a change in hydrophobic environments using a lipophilic probe such as halothane, and secondly in monitoring the effects of hyperthermia, a treatment whose effectiveness may involve changes at the level of the plasma membrane. Under conditions of continuous delivery, a resonance which is not detected in the spectra of halothane in excised tissue appears 5 ppm downfield from the resonance for halothane localized in tissues. A rotating frame experiment is used to show that this resonance is derived from anesthetic absorbed on the tissue surface.

Animals↗