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Biomedical subjects

R E Anderson

Publications and source records attributed to R E Anderson.

At least 343 records · Page 19Linked to original sources
PubMed1983

Neutral lipids of frog and rat rod outer segments.

Neutral lipids of rod outer segments (ROS) from frog and rat comprise roughly 10 mol% of the total lipids and consist of free sterol, free fatty acids, and 1,2-diglycerides, but contain no detectable sterol esters or triglycerides. Expressed as nmol per mg ROS protein, the levels of both free fatty acids and free sterol are higher in the rat than in the frog, whereas the diglycerides in frogs are about four times higher than in rats. The level of 22:6 omega 3 in the free fatty acids fraction of the frog is twice that of the rat, although the level of 22:6 omega 3 in both the frog and rat free fatty acids is lower than in any of the glycerolipids. The diglyceride fraction from both animals consists almost entirely of two molecular species: in the frog, the C-38 and C-40 type predominate in a molar distribution of 52 and 42% respectively, whereas in the rat, the C-36 and C-38 types are most abundant in a molar distribution of 28 and 60%, respectively. Comparison of the diglyceride fatty acid and molecular species compositions with those of phosphatidylinositol and phosphatidic acid led to the suggestion that ROS diglycerides are derived from phosphatidylinositol.

Animals↗
PubMed1983

Brain pH in focal cerebral ischemia and the protective effects of barbiturate anesthesia.

Intracellular brain pH was measured with a lipid-soluble, pH-sensitive fluorescent indicator in 16 squirrel monkeys. Eight of these were under halothane anesthesia and eight under barbiturate anesthesia. Measurements were taken before, during, and after focal incomplete ischemia. Brain pH following 3 h of cerebral focal ischemia changed from a normal value of 7.0 to 6.5 and 6.2 in animals studied under barbiturate and halothane anesthesia, respectively. Brain pH returned toward normal after flow was restored in animals under barbiturate anesthesia but continued to deteriorate in animals under halothane anesthesia.

Animals↗
PubMed1983

Phosphoinositide metabolism in the retina: localization to horizontal cells and regulation by light and divalent cations.

Isolated retinas from Xenopus laevis incorporated greater amounts of [3H]inositol and 32Pi into phosphoinositides when incubated in light than did control retinas incubated in the dark. Inositol was primarily incorporated into phosphatidylinositol (83-86%), while phosphate labeled the polyphosphoinositides (72-79%). The incorporation of radioactive glycerol, serine, choline, or ethanolamine into retinal lipids was unaffected by light. Following incubation with [3H]inositol, the cell type involved in the light response was identified by light and electron microscope autoradiography to be the horizontal cell. These results are consistent with a classic phosphatidylinositol effect in the retina. An interesting feature of this response is that the stimulus (light) is received in the photoreceptor cell and the effect is manifest in the horizontal cell.

Animals↗
PubMed1983

Dynamic tomographic digital subtraction angiography using temporal filtration.

A variation of temporal recursive filtering for intravenous and intra-arterial digital subtraction angiography (DSA) is described. It results in a dynamic tomographic DSA display that may improve intravenous DSA performance by removing the confusion introduced by vessel overlap and reducing the severity of motion artifacts. A conventional circular tomographic apparatus was modified by the addition of a 23-cm image intensifier-television chain and made to run continuously at one revolution each 1.5 seconds. The video output was processed by the recursive filter in a two-step process resulting in a dynamic tomographic display of arterial opacification. Theory and results of initial animal studies are presented.

Angiography↗
PubMed1983

Clinical intra-arterial digital subtraction imaging. Use of small volumes of iodinated contrast material or carbon dioxide.

Forty patients were examined with intra-arterial digital subtraction angiography (DSA) using meglumine iothalamate (202 mg iodine/ml) or CO2 as a contrast medium. Diagnostic studies were obtained in all patients. The use of CO2 resulted in diagnostic examinations of the common femoral artery to the level of the trifurcation. The use of CO2 and low-iodine-content contrast material reduced the iodine dosage, and temporal bandpass filtration DSA permitted a lower entrance exposure than pulsed systems. It is concluded that intra-arterial DSA, using the techniques described in this paper, will become a more important and widely used procedure than it currently is.

Angiography↗
PubMed1983

Manpower supply and demand in pathology.

Recently physicians, the federal government, and medical specialty societies have shown increasing interest in manpower needs in medicine and in the medical specialties. Since 1976 the Joint Task Force on Pathology Manpower of the American Society of Clinical Pathologists, the College of American Pathologists, and the Association of Pathology Chairmen has completed and published three reports on pathology manpower supply and demand. The results of these studies agree with a recently completed study by a federally mandated commission. These studies show pathology manpower in the early 1980s is in good balance between supply and demand. They also indicate this equilibrium will continue until 1990 unless unanticipated changes in supply and demand take place.

Pathology, Clinical↗
PubMed1983

Effect of whole-body irradiation of mice on the number of background plaque-forming cells.

Mice were exposed in whole-body fashion to several doses of radiation and killed at various times thereafter for a determination of the number of background plaque-forming cells (PFCs) as assayed on either sheep erythrocytes or bromelain-treated autologous mouse erythrocytes. Increased numbers of both types of PFC were found in the irradiated groups. These increases were dependent on radiation dose and time after exposure. They did not appear to be caused by a disruption of normal lymphocyte traffic or a switch in immunoglobulin isotype. An increased number of PFCs on bromelain-treated mouse RBCs but not on sheep RBCs were found in irradiated congenitally athymic nude mice. On the basis of this and related observations, background PFCs on bromelain-treated mouse RBCs and on sheep RBCs appear to fall under different forms of homeostatic control.

Animals↗
PubMed1983

Evidence for rod outer segment lipid peroxidation following constant illumination of the rat retina.

Constant illumination for three days (100-125 foot-candles) caused degeneration of photoreceptor cells in the albino rat retina and was accompanied by a reduction in the levels of docosahexaenoic acid (22:6 omega 3), the major polyunsaturated fatty acid in rod outer segments (ROS). An increase in the level of lipid conjugated dienes, a measure of lipid hydroperoxides, also was observed in ROS after 24-72 hours of constant illumination. These data support the suggestion that peroxidation of long-chain polyunsaturated fatty acids in ROS may be a factor in light-induced retinal degeneration.

Animals↗
PubMed1983

The use of vitreous fluorophotometry to distinguish between diabetics with and without observable retinopathy: effect of vitreous abnormalities on the measurement.

Ten age-matched normals, diabetics with retinopathy, and diabetics without observable retinopathy were evaluated by vitreous fluorophotometry (VFL) using a 0.15 mm and a 0.45 fiberoptic probe in a photomultiplier system as well as a commercially available photodiode instrument to determine whether differences in intraocular sodium fluorescein levels could be detected among the three groups. Each subject was injected in the antecubital vein with 7 mg/kg of sodium fluorescein (25% solution) and measurements were taken 1 hr postinjection at 4.5 mm and 7.5 mm from the retina. The influence of choroidal fluorescein and ocular pigmentation are reduced at these locations. We found that a breakdown in the blood-ocular barrier may not be present early in the course of diabetes. Furthermore, no significant difference was found between normals and diabetics without retinopathy. Although the mean value for vitreous fluorescein was significantly higher in diabetics with retinopathy compared to normals, several of the diabetics with retinopathy had values in the normal range. These results differ from those previously reported in the literature. However, our studies took into consideration several factors not considered by other investigators, such as ocular pigmentation, choroidal fluorescence, slit width, and vitreous changes, that may have significant effects on the fluorophotometry values.

Adolescent↗
PubMed1983

Alteration of retinal choline metabolism in an experimental model for photoreceptor cell degeneration.

The choline analog hemicholinium-3 causes selective degeneration of the cones and rods in the rabbit retina. These experiments examine some biochemical effects of hemicholinium-3 on metabolic pathways involved in choline metabolism. No effect of the drug on several important photoreceptor biosynthetic functions was found: leucine incorporation into TCA-precipitable material, glycerol incorporation into phospholipids, and phosphatidylcholine formation by either base exchange or choline phosphotransferase activity. However, hemicholinium-3 does selectively affect free choline use: high-affinity uptake, phosphorylation and subsequent incorporation into lipid. In each instance, hemicholinium-3 causes a significant inhibition of control activity at a concentration of 30 microM, a dosage that causes complete photoreceptor outer segment degeneration in mammalian retinas. Thus, it seems that the enormous synthetic requirements for phosphatidylcholine leave the photoreceptor cell in fragile metabolic balance, and transient alteration of this balance may destroy the outer segment.

Animals↗
PubMed1982

Low dose radiosensitivity of alloimmune cytotoxic T cells.

Low dose radiosensitivity of in vitro generated alloimmune murine cytotoxic T lymphocytes (CTL) was studied. It appears that a subset of CTL exists that can be killed with 10-25 rad of x rays. These radiosensitive CTL are Lyt-1,2+ T lymphocytes. Analyses of cytotoxicity by chromium release assays indicate that the radiosensitive CTL are present in responder spleen cell cultures from all strains of mice tested. The generation of these effector cells is most pronounced in animals of the C57BL background. The mechanism of low dose radiosensitivity appears to be interphase death.

Animals↗
PubMed1982

The influence of vitreous change on vitreous fluorophotometry.

Thirteen patients with retinitis pigmentosa were graded in terms of vitreous change and compared by vitreous fluorophotometry to an equal number of normal patients. A highly significant difference was found between groups. A high correlation was also noted between severity of vitreous change and midvitreous fluorophotometry values. Certain types of vitreous detachments appear to produce a characteristic "cancer hump" in the resultant data. A possible explanation for the increased values is discussed.

Adult↗
PubMed1982

Ultrastructural immunocytochemical localization of carbonic anhydrase in normal and calcitonin-treated chick osteoclasts.

Carbonic anhydrase was localized in osteoclasts by light and electron microscopy using a preembedding peroxidase-antiperoxidase staining method. Osteoclasts on the endosteal surface of the metatarsi of calcitonin-treated and untreated (control) chicks were studied. A positive staining reaction was seen in the cytosol, in the Golgi apparatus, in and on vesicles, on the plasma membrane of the ruffled border, and on the bone surface beneath control osteoclasts. After calcitonin treatment, positive staining reactions were seen at the same sites except that staining was absent on the plasma membrane and endosteal bone surface. The morphology of osteoclasts from calcitonin-treated chicks was indicative of cell inactivity. The carbonic anhydrase which was bound to the plasma membrane of the ruffled border is appropriately arrayed for hydrogen ion secretion and subsequent mineral dissolution. The presence of the enzyme within lysosomelike vesicles and on the endosteal surface beneath active cells suggests that it may be released into the resorbing zone along with the lysosomal hydrolases. The function of the extracellular enzyme is also unknown.

Animals↗