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R R Warner

Publications and source records attributed to R R Warner.

At least 37 records · Page 2Linked to original sources
PubMed1986

Water content from analysis of freeze-dried thin sections.

The analytical electron microscope and related electron beam instruments are uniquely able to measure the water content of biological tissue at a subcellular level. An analysis of the Rick procedure for quantifying this water content (Dörge et al., 1978; Rick et al., 1979) reveals a hidden assumption; namely, that the sample and standard densities, in the hydrated state, must be equal. In general this will not be valid. Equations are derived that do not invoke this hidden assumption. These equations show that errors in using the Rick technique for measuring water content should be small, a few per cent, unless the sample contains a very heterogeneous distribution of mass or the water content of the standard is a poor representation of the sample. For freeze-dried samples with extensive mass heterogeneity, such as skin, the equations for calculating water content presented in this paper should be used.

Animals↗
PubMed1986

Do indole markers predict carcinoid heart disease?

Deficiency of tryptophan with elevated serum serotonin and liver dysfunction are the prerequisites for the experimental production of cardiac lesions in the guinea pig model of carcinoid syndrome. To apply the above principles in human subjects with carcinoid disease, various indole markers were compared in patients with or without heart involvement, to a group of normal subjects. In the present study, plasma tryptophan (T), serotonin (5HT), and urinary 5 hydroxyindoleacetic acid (5HIAA) measurements were made in 18 (group 1) patients with carcinoid syndrome and 24 normal individuals (group 2). Of the 18 patients, seven (group 1A) had valvular involvement and 11 (group 1B) had none, as determined by clinical, roentgenographic, and echocardiographic (M-mode and 2-D) techniques. Analysis of the above data shows that unlike animal models, there is no difference in serum tryptophan, serum serotonin, and urinary 5 hydroxyindoleacetic acid levels, in patients with carcinoid syndrome with or without cardiac involvement (p greater than 0.05). Furthermore, the data confirm that serum tryptophan, a substrate in carcinoid syndrome, is decreased and in serum serotonin and urinary 5 hydroxyindoleacetic acid, the metabolites are elevated.

Adult↗
PubMed1985

Control of carcinoid syndrome with hepatic artery embolization.

Eighteen patients with metastatic carcinoid were treated by hepatic artery embolization with Gelfoam or polyvinyl alcohol foam for control of the carcinoid syndrome. Seventeen showed subjective or objective clinical improvement, including less skin flushing, diarrhea, and bronchospasm. Fourteen showed improvement in biochemical indices, including decreased urinary 5-hydroxyindoleacetic acid levels. The mean life span of the treated patients from the first episode of flushing to the time of this report was 5.4 years, and half of the patients are still alive. This survival time compares favorably with previous reports of survival of 3.2 years from the onset of flushing.

Adult↗
PubMed1982

Analysis of standing droplets in rat proximal tubules.

Volume, osmolality, and concentrations for Na, Cl, and raffinose have been measured as a function of time in standing droplets within rat intermediate and late proximal tubules. Standing droplet reabsorption proceeds without the development of a measurable osmotic difference across the epithelium. After 140 s of tubular exposure, droplet-to-plasma concentration differences are observed for raffinose, Na, and Cl with the observed Na concentration difference, usually referred to as limiting gradient, being approximately 9 mM. It is possible that a smaller or even no limiting difference would be attained with longer exposure times. Previous values measured for the limiting Na concentration in the rat proximal tubule were determined before the attainment of constant concentrations. Assuming that the Na concentration we measured is the limiting value, we estimate that active NaCl transport accounts for a very small fraction, less than 6%, of the volume reabsorption; using an alternative approach of fitting a theoretical model to our experimental data, active NaCl transport is again estimated to account for only 6% of the total reabsorbate. The previous interpretation that a limiting Na concentration gradient constitutes the most direct evidence for active Na transport may be in error; the gradient we measure can be modeled without incorporating active NaCl transport.

Animals↗
PubMed1980

Isosmotic volume reabsorption in rat proximal tubule.

A theoretical model incorporation both active and passive forces has been developed for fluid reabsorption from split oil droplets in rat intermediate and late proximal tubule. Of necessity, simplifying assumptions have been introduced; we have assumed that the epithelium can be treated as a single membrane and that the membrane "effective" HCO3 permeability is near zero. Based on this model with its underlying assumptions, the following conclusions are drawn. Regardless of the presence or absence of active NaCl transport, fluid reabsorption from the split oil droplet is isosmotic. The reabsorbate osmolarity can be affected by changes in tubular permeability parameters and applied forces but is not readily altered from an osmolarity essentially equal to that of plasma. In a split droplet, isosmotic flow need not be a special consequence of active Na transport, is not the result of a particular set of permeability properties, and is not merely a trivial consequence of a very high hydraulic conductivity; isosmotic flow can be obtained with hydraulic conductivity nearly an order of magnitude lower than that previously measured in the rat proximal convoluted tubule. Isosmotic reabsorption is, in part, the result of the interdependence of salt and water flows, their changing in parallel, and thus their ratio, the reabsorbate concentration being relatively invariant. Active NaCl transport can cause osmotic water flow by reducing the luminal fluid osmolarity. In the presence of passive forces the luminal fluid can be hypertonic to plasma, and active NaCl transport can still exert its osmotic effect on volume flow. There are two passive forces for volume flow: the Cl gradient and the difference in effective osmotic pressure; they have an approximately equivalent effect on volume flow. Experimentally, we have measured volume changes in a droplet made hyperosmotic by the addition of 50 mM NaCl; the experimental results are predicted reasonably well by our theoretical model.

Animals↗
PubMed1978

Compartmental analysis of Na efflux across ileum mucosal membrane.

A new tracer analysis technique has been developed for efflux from a three compartment series system. With this technique, results are based on pools contributing to efflux and not on total tissue pools. The use of this technique is illustrated in a study of Na efflux across the luminal membrane of rabbit ileum. Na efflux was described by two exponentials with half-times of 1.78 min and 13.5 min. The fast component, with a flux of 68.0 mumoles/h cm2 and a calculated Na concentration of 166 mM, was identified as an extracellular compartment. The slow component, with a flux of 13.2 mumoles/h cm2 and Na concentration of 86 mM, was identified with efflux across the mucosal membrane of epithelial cells.

Animals↗
PubMed1978

Anaesthesia for the carcinoid syndrome: a report of nine cases.

Anaesthesia for nine patients with the carcinoid syndrome is described. With the exception of one case in which severe bronchospasm and hypertension occurred, complications were minor. Steroids, aprotonin and methotrimeprazine appear to be useful agents in the management of such patients. An anaesthetic technique employing thiopentone, pancuronium and nitrous oxide proved satisfactory.

Aged↗
PubMed1976

Sex ratio, sex change, and natural selection.

We describe the analogy between the theory of natural selection on sex ratio in newborn gonochores (which will not change sex), and on the age of sex change in sequential hermaphrodites (which are all born into one sex and change to the other later on). We also discuss the conditions under which natural selection favors sequential hermaphrodites over gonochores and vice versa. We show that, in a nearly stable population of nearly constant age composition, selection favors a rare mutant if it increases the prospective reproduction of its newborn bearers that are (or while they are) members of one sex by a percentage exceeding the percentage loss to the other sex.

Aging↗
PubMed1975

Electron probe analysis of calcium transport by small intestine.

Calcium transport in small intestine of rat and chick has been studied at the cellular level using the electron probe X-ray microanalyzer. Tissues were examined directly after removal as well as after incubation in a calcium solution. In both preparations, discrete calcium localizations were found associated with intracellular and extracellular goblet cell mucus. The in vitro preparations showed calcium in transit across the absorptive epithelium in discrete localizations. Although the primary path of transport was along lateral cell borders, some localizations were found in the cytoplasm in a supranuclear position. The effect of vitamin D depletion and repletion was to decrease and increase, respectively, the number of calcium localizations in transit across the epithelium. These results suggest that calcium is transported while in a sequestered form and indicate that goblet cell mucus plays a role in this transport process.

Aging↗