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Biomedical subjects

M Graham

Publications and source records attributed to M Graham.

At least 91 records · Page 5Linked to original sources
PubMed1982

Simultaneous and successive contrast effects in the perception of depth from motion-parallax and stereoscopic information.

Prolonged inspection of a three-dimensional corrugated surface resulted in a successive contrast effect, or aftereffect, of depth, whereby a subsequently-viewed physically-flat test surface appeared to be corrugated in depth with the opposite phase to the adapting surface. The aftereffect occurred both when the depth was specified by motion parallax, in the absence of all other sources of depth information, and when it was specified solely by stereoscopic information. The depth aftereffect was measured by 'nulling' the apparent depth in the test surface with physical relative motion or binocular disparity until the test surface appeared flat. Up to 70% of the depth in the adapting surface was necessary to null the aftereffect. Simultaneous contrast effects in the perception of three-dimensional surfaces were used to investigate the spatial interactions that exist in the processing of motion-parallax and stereoscopic information. A physically vertical surface appeared to slope in depth in the opposite direction to the slope of a surrounding surface. In this case up to 50% of the slope of the inducing surface was necessary to null the contrast effect. Similar results were again obtained for motion-parallax and stereoscopic depth.

Adaptation, Ocular↗
PubMed1982

Rate of diffusion of Solu-Medrol across the silastic membranes of breast prostheses-an in vitro study.

Many plastic surgeons have used steroids in breast prostheses in augmentation and postmastectomy reconstruction to prevent capsular contracture. The detection and incidence of complications have increased during the last several years. It is probable that the incidence of complications is related to two factors. First, clinicians have used the same doses in the smaller outer compartments of bilumen implants, giving a much higher concentration of steroid. Second, the more recent implants have thinner envelopes. Tritiated Solu-Medrol was placed in the outer lumen of the bilumen Heyer-Schulte, McGhan, and Surgitek prostheses, and in the only lumen of inflatable Mammatech and Heyer-Schulte prostheses. Diffusion of the Solu-Medrol from each of these identically sized prostheses into the surrounding saline bath was measured with a liquid scintillation counter. Diffusion rates provided concentration-dependent, as predicted by Donnan-Gibbs equilibrium. The silicon gel in bilumen implants was found to represent a second Donnan-Gibbs equilibrium and result in a lower diffusion rate because of affinity for the steroid.

Breast↗
PubMed1982

Liver adenosine triphosphate (ATP) in hypoxia and hemorrhagic shock.

Reduction of liver ATP in proportion to the severity of shock and hypoxia is well known. We have studied the interrelationships among arterial oxygenation, arterial pH, and liver ATP in experimental hypoxia and in hemorrhagic shock in rats. No significant correlation was found between liver ATP and arterial pH in both hemorrhagic shock and hypoxia and between liver ATP and arterial PO2 in hypoxia. Induction of experimental observations suggest that in this form of hemorrhagic shock, arterial pH may be a sensitive indicator of decreased hepatic perfusion and impaired liver ATP production.

Acidosis, Respiratory↗
PubMed1981

Staging Meniere's disease and reporting results in Meniere's disease: symposium panel discussion.

At its recent spring meeting, the American Neurotologic Society devoted a portion of its program to a symposium on staging Meniere's disease and reporting results. One of the problems discussed, was which preoperative audiogram should be used for reporting results of any treatment. I think that it is very important that we, as otologists, try to look at Meniere's disease or any inner ear dysfunction in a more scientific way. Some of you may feel, on initial evaluation of this material, that it is too cumbersome to be practical in your daily clinical work. However, we feel we have put forth a reasonable staging system and method of reporting results that can be quite helpful once the simple routine of using them has become established. The vertigogram, for example, which is designed to be very simple and not require any sophisticated equipment, should be as easy to read as an audiogram. If we try to approach the vagaries of Meniere's disease or any inner ear dysfunction in a more scientific fashion, I am sure that in several years we will be in a much better position collectively to evaluate our results and to help our patients. This type of comprehensive staging system for all of the components in Meniere's disease or any inner ear dysfunction will enable us to objectify diagnoses and treatment results so that they can be easily compared. We have put forth some of the ideas and methods that we think will help us arrive at a consensus for reporting results. We encourage you to try some of the suggestions presented in this article and welcome your comments and ideas for improving this staging system and method for reporting results.

Audiometry↗
PubMed1980

Performance characteristics of a commercial ECG gate.

A commercial ECG gate was tested to evaluate its ability to predict accurately the time of end-systole. The predicted times followed the manufacturer's specifications quite well. These times were compared with the actual times of end-systole as determined by computer-derived left-ventricular time-activity curves using Tc-99m-labeled red blood cells. Although there was moderate scatter, the predicted times of end-systole correlated well with the actual times (n = 59, r = 0.829). If the left-ventricular ejection fraction was calculated using the predicted time of end-systole, the error would be 0.03, or less, for 95% of the subjects.

Cardiac Output↗
PubMed1979

Genital cancer in wives of penile cancer patients.

We identified the wives or ex-wives of 227 males of the 256 reported with cancer of the penis to the New York State Cancer Registry from Upstate New York from 1960-64. Utilizing the Registry, death certificates, hospital and physician records, we ascertained those wives who developed cancer at any site from 1951-1975. We generated expected numbers of cases of cancer at each site by applying the age specific incidence rates experienced by women of a specific age in a specific year designated by the age of the wife of the index case in each year, estimating withdrawals from age-specific death rates. Thus, our expected numbers are based on the experience of the women in Upstate New York with traits like those of spouses of the men in the same population with cancer of the penis. We found significantly more cases of cancer of the cervix than expected. This was not true for other sites of cancer.

Adult↗
PubMed1979

Within-species variation in the development of ultrasonic signaling of preweanling rats.

The development of litter and individual differences in the rate of ultrasonic signaling of neonatal rats was studied. Systematic variations among litters and individuals emerged, without differential treatment. These differences were not correlated with variations in general development as indexed by body weight. Two experiments using a cross-fostering design showed that litter differences developed independently of variations in postnatal environment. These results indicate that the variations among litters in ultrasound rate have a prenatal, possibly genetic, etiology and may represent reliable indicants of response to environmental stress.

Animals↗
PubMed1979

Ultrasound diagnosis of interstitial pregnancy: findings and pitfalls.

The diagnosis of an unruptured interstitial gestation can be made by means of ultrasound examination. The most specific finding is an incomplete myometrial mantle around the sac. An eccentrically placed sac and failure to demonstrate the sac within the uterine cavity, i.e., near the internal os on the longitudinal scans, may be helpful ancillary findings. The differential diagnosis must take into consideration a pregnancy within one horn of a bicornuate uterus and a pregnancy within a myomatous uterus. Although this is a rare condition, it carries significant mortality if it ruptures. Diagnosis prior to rupture will reduce mortality and offer the possibility of preserving reproductive capabilities.

Adult↗
PubMed1979

Plasma pentazocine radioimmunoassay.

A sensitive and specific radioimmunoassay of dog and human plasma pentazocine is described. Rabbit antiserum and the second antibody method separated bound from free pentazocine. The radioimmunoassay employed an 125I-labeled radioligand and required extraction from the sample prior to quantitation. The method had a detection limit of approximately 200 pg/assay tube (1 ng/ml). The assay was used successfully to measure pentazocine in the plasma of beagle hounds given 0.3 mg of pentazocine/kg iv. The decline in plasma levels fitted a two-compartment body model with a 100-min mean overall half-life and a 3.2-liters/hr mean plasma clearance rate.

Animals↗
PubMed1979

Motion parallax as an independent cue for depth perception.

The perspective transformations of the retinal image, produced by either the movement of an observer or the movement of objects in the visual world, were found to produce a reliable, consistent, and unambiguous impression of relative depth in the absence of all other cues to depth and distance. The stimulus displays consisted of computer-generated random-dot patterns that could be transformed by each movement of the observer or the display oscilloscope to simulate the relative movement information produced by a three-dimensional surface. Using a stereoscopic matching task, the second experiment showed that the perceived depth from parallax transformations is in close agreement with the degree of relative image displacement, as well as producing a compelling impression of three-dimensionality not unlike that found with random-dot stereograms.

Cues↗
PubMed1978

Glutathione S-transferase in human lymphoid cell lines and fractionated peripheral leucocytes.

Glutathione S-transferase activity was identified in cytosol from human lymphoid-cell lines and peripheral leucocytes (polymorphonuclear-leucocyte/monocyte and small-lymphocyte fractions) and compared with human liver enzyme. The findings of closely similar elution volume in gel filtration, substrate (1-chloro-2,4-dinitrobenzene) and inhibitory (probenecid) kinetics indicate that the liver, leucocyte and lymphoid-cell transferases are closely related. The interaction of reduced glutathione and 1-chloro-2,4-dinitrobenzene was shown to occur in intact-lymphoid-cell culture, to be linear with time and quantity of cells and to have kinetics similar to those of the enzyme reaction catalysed by cytosol.

Cell Line↗
PubMed1977

Ultrasound emission in infant rats as an indicant of arousal during appetitive learning and extinction.

Infant rats rewarded for crawling by being allowed to suckle on the dry nipple of an anesthetized dam showed a decreasing rate of ultrasound production during acquisition and an increasing rate during extinction. These results suggest that infant rats can be stressed and are aroused as a result of successive nonrewards just as adult rats are. In addition, these results do not support the hypothesis that infant rats lack inhibitory mechanisms related to poorly developed neural centers.

Animals↗