Showing papers by "Georgetown University published in 1977"

The [14C]deoxyglucose method for the measurement of local cerebral glucose utilization: theory, procedure, and normal values in the conscious and anesthetized albino rat.

Abstract: — A method has been developed for the simultaneous measurement of the rates of glucose consumption in the various structural and functional components of the brain in vivo. The method can be applied to most laboratory animals in the conscious state. It is based on the use of 2-deoxy-D-[14C]glucose ([14C]DG) as a tracer for the exchange of glucose between plasma and brain and its phosphorylation by hexokinase in the tissues. [14C]DG is used because the label in its product, [14C]deoxyglucose-6-phosphate, is essentially trapped in the tissue over the time course of the measurement. A model has been designed based on the assumptions of a steady state for glucose consumption, a first order equilibration of the free [14C]DG pool in the tissue with the plasma level, and relative rates of phosphorylation of [14C]DG and glucose determined by their relative concentrations in the precursor pools and their respective kinetic constants for the hexokinase reaction. An operational equation based on this model has been derived in terms of determinable variables. A pulse of [14C]DG is administered intravenously and the arterial plasma [14C]DG and glucose concentrations monitored for a preset time between 30 and 45min. At the prescribed time, the head is removed and frozen in liquid N2-chilled Freon XII, and the brain sectioned for autoradiography. Local tissue concentrations of [14C]DG are determined by quantitative autoradiography. Local cerebral glucose consumption is calculated by the equation on the basis of these measured values. The method has been applied to normal albino rats in the conscious state and under thiopental anesthesia. The results demonstrate that the local rates of glucose consumption in the brain fall into two distinct distributions, one for gray matter and the other for white matter. In the conscious rat the values in the gray matter vary widely from structure to structure (54-197 μmol/100 g/min) with the highest values in structures related to auditory function, e.g. medial geniculate body, superior olive, inferior colliculus, and auditory cortex. The values in white matter are more uniform (i.e. 33–40 μmo1/100 g/min) at levels approximately one-fourth to one-half those of gray matter. Heterogeneous rates of glucose consumption are frequently seen within specific structures, often revealing a pattern of cytoarchitecture. Thiopental anesthesia markedly depresses the rates of glucose utilization throughout the brain, particularly in gray matter, and metabolic rate throughout gray matter becomes more uniform at a lower level.

The export behavior of smaller-sized wisconsin manufacturing firms

Abstract: A summary of principal findings regarding the export behavior of 423 small- and medium-sized Wisconsin manufacturing firms. Data were classified according to stages in the export development process and analyzed by multiple regression.

Restitution: A New Paradigm of Criminal Justice

Abstract: This paper will analyze the breakdown of our system of criminal justice in terms of what Thomas Kuhn would describe as a crisis of an old paradigm-punishment. I propose that this crisis could be solved by the adoption of a new paradigm of criminal justice-restitution. The approach will be mainly theoretical, though at various points in the discussion the practical implications of the rival paradigms will also be considered. A fundamental contention will be that many, if not most, of our system's ills stem from errors in the underlying paradigm. Any attempt to correct these symptomatic debilities without a reexamination of the theoretical underpinnings is doomed to frustration and failure. Kuhn's theories deal with the problems of science. What made his proposal so startling was its attempt to analogize scientific development to social and political development. Here, I will simply reverse the process by applying Kuhn's framework of scientific change to social, or in this case, legal development.'

Statistical methods for studying multiple primary malignant neoplasms.

Abstract: Case reports and case series dealing with multiple primary malignant neoplasms provided useful criteria for defining and documenting this phenomenon. The formation of tumor registries greatly aided in identifying a sufficient number of multiple primary cancer patients and facilitated case-control comparisons. Reports of two or more neoplasms occurring together in the same individual do not constitute proof of a significant association; the tumors must be shown to occur together more frequently than expected by chance. The person-years approach applied to data derived from a well-defined population makes it possible to compare the observed and expected number of subsequent primary cancers. The results of the most sophisticated procedures are no better than the quality of the data, however, and one must critically examine possible sources of bias before accepting statistical significance as representing biologic significance.

Changes in distribution of platelet membrane glycoproteins in patients with myeloproliferative disorders.

Abstract: Glycoproteins have been discovered to be important to platelet function both in normal and pathological states. We have studied membrane glycoprotein patterns in 16 patients with various myeloproliferative disorders. There was an abnormal ratio of glycoprotein I glycoprotein IV in patients with myeloproliferative disease compared with controls. There was no discernible correlation between glycoprotein pattern and aggregation response or platelet count, but patients with megathrombocytes had higher values for glycoprotein IV than those without megathrombocytes. These experiments suggest that patients with myeloproliferative disorders may have alterations in membrane glycoproteins that could alter platelet function.

Anatomical Grading of Supratentorial Arteriovenous Malformations for Determining Operability

Abstract: After the study of over 300 angiograms of supratentorial cerebral arteriovenous malformations (AVM's), the authors have formulated an anatomical grading scheme of I to IV to correspond to the degrees of surgical difficulty for total obliteration. The grading is based upon the number of directly participating arteries for which there is a standardized nomenclature. Occasionally, allowance for clinical grading, in addition to this anatomical grading, must be made. Also, for the anticipation of morbidity, but not mortality, the location of the lesion is important. The authors present the postoperative results in a series of 49 patients to demonstrate the clinical usefulness of the grading scheme.

Effect of Magnesium Sulfate On Cardiovascular Hemodynamics

Abstract: to characterize its effect on cardiovascular hemodynamics. Although the biochemical effects of magnesium administration as well as the effects on the cardiac conduction system,17 glomerular filtration rate,18.19 and neuromusculur function2° have been well studied, there have been no reported investigations concerning the effects of magnesium sulfate on cardiovascular hemodynamics in humans. The present study sought to document the cardiovascular hemodynamic consequences of intravenous magnesium sulfate administration in normal and hypertensive subjects.

Maturation of the Rabbit Alveolar Macrophage during Animal Development. I. Perinatal Influx into Alveoli and Ultrastructural Differentiation

Abstract: Maturation of the Rabbit Alveolar Macrophage during Animal Development. I. Perinatal Influx into Alveoli and Ultrastructural Differentiation

Experimental Photocoagulation of the Human Retina: I. Correlation of Physical, Clinical, and Pathologic Data

Abstract: • Thirty-eight retinal burns were inflicted by a modified xenon-arc photocoagulator in the eyes of eight human volunteers. The ophthalmoscopic characteristics of these lesions were correlated with the degree of histopathologic damage. Definitive clinical criteria that helped to predict the severity of the retinal burns were established. The dose of radiant energy received was further correlated with the histopathologic changes in determining the threshold of safety standards of bright flashes of white light to the human eye. Lesions from patients with blue irises were produced by considerably higher dose rates than comparable lesions from patients with brown irises and the fovea was more susceptible to damage than the rest of the retina. ( Arch Ophthalmol 95:1035-1040, 1977)

The effect of a token economy on dietary compliance for children on hemodialysis

Abstract: Adherence to dietary restrictions is a recurring problem for children on hemodialysis. The effect of behavior modification in maintaining dietary control is reported for four patients aged 11 to 18 years. Weight gain, potassium level, and blood urea nitrogen were utilized as criteria measures. A token reinforcement program implemented by the hemodialysis team resulted in significant changes in the dietary pattern of the children. The average weight gain between dialysis sessions for the four subjects during treatment was reduced by 45% and the degree of weight fluctuation was lessened. Potassium levels and BUN were controlled to their appropriate level for subjects who initially exceeded the criterion level. With the withdrawal of weight gain from the contingency system, increase of weight gain between dialysis sessions was noted for all subjects.

Development of a Chemically Defined Medium for the Synthesis of Actinomycin D by Streptomyces parvulus

Abstract: A chemically defined medium, consisting of d-fructose, l-glutamic acid, l-histidine, K 2 HPO 4 , MgSO 4 ·7H 2 O, ZnSO 4 ·7H 2 O, CaCl 2 ·2H 2 O, FeSO 4 ·7H 2 O, CoCl 2 ·6H 2 O, and deionized water, was developed for synthesis of high yields (500 to 600 μg/ml) of actinomycin D by Streptomyces parvulus . Under these nutritional conditions, growth and actinomycin formation did not follow a typical trophophase-idiophase pattern. The amino acids appeared to have a sparing action on the utilization of d-fructose which was slowly and incompletely metabolized during mycelium development and antibiotic production. A significant repression of actinomycin synthesis by S. parvulus was observed when d-glucose (0.01 to 0.25%) was added to the culture medium. The repression was not due to a decline in the pH of the medium during glucose catabolism.

Distance correction for precordial electrocardiographic voltage in estimating left ventricular mass: an echocardiographic study.

Abstract: This study was undertaken to assess both the relation between echocardiographic measurement of left ventricular (LV) mass and commonly used electrocardiographic criteria for LV hypertrophy and the effect of the distance from the center of LV mass to the anterior chest wall on precordial voltage. Echocardiograms and standard 12-lead electrocardiograms were obtained on 100 persons, ages 3 to 79. The correlation coefficients of echocardiographically determined LV mass with ECG precordial voltage (SV1 + RV5 or V6), the Estes point score system, and a VL4 wave voltage were .686, .721, and .531, respectively. Extrapolating from the dipole nature of the heart, the precrodial voltage was multiplied by the square of the chest wall to mid-LV distance to correct for the loss of energy across the distance from LV to recording electrode. Utilizing this correction, a much improved precordial voltage estimation of LV mass (r = .846) was obtained. We conclude that the distance of the center of LV mass from the chest wall influences the amplitude of recorded precordial voltage and that correction for this influence improved the correlation of precordial voltage with LV mass.

Theory of Nonspecular Reflection. Effects for an Ultrasonic Beam Incident on a Solid Plate in a Liquid

Abstract: Poles and zeroes of the infinite plane wave amplitude reflection coefficient are used to derive a theoretical prediction of the nonspecular reflection effects which have been observed for an ultrasonic beam incident on an isotropic solid plate in a liquid. It is shown that there are two types of nonspecular reflections, and they can be characterized in terms of a single parameter which requires a knowledge of the imaginary part of a pole of the infinite plane wave reflection coefficient. Theoretical predictions of nonspecular reflection intensities are presented. Finally, it is shown that the reflection characteristics for high-frequency beams incident on thick plates are the same as those expected for the reflection from a single liquidisolid interface, i.e., two infinite half-spaces. T INTRODUCTION HEORETICAL and experimental aspects of beam displacement phenomena have been actively studied since 1947 when Coos and Hanchen [ l ] demonstrated that a beam of light is displaced from the expected geometrically reflected beam upon reflection from the interface between two transparent media. In 1950 Schoch predicted [2] and later experimentally verified [3 J the beam displacement effect for an acoustic beam incident on a liquid/solid (L/S) interface. Schoch’s theory predicted that an incident bounded acoustic beam would be nonspecularly reflected in that the reflected beam would be displaced laterally along the interface while the reflected beam profile retained the same general shape as the incident beam profile. analysis of nonspecular reflection phenomena has been used Although the basic framework of Schoch’s theoretical Manuscript received May 17, 1976. This work was supported by the L. E. Pitts was with the Department of Physics, Georgetown UniverOffice of Naval Research, U.S. Navy. sity, Washington, DC 20057. He is now with the Department of Physics, Mary Washington College, Fredericksburg, VA 22401. sity, Washington, DC 20057. He is now with the Schlumberger-Doll Research Center, Ridgefield, CT 06877. sity, Washington, DC 20057. T. J. Plona was with the Department of Physics, Georgetown UniverW. G. Mayer is with the Department of Physics, Georgetown Univerby later authors [4] , [ 5 ] , his theory did not account for two experimentally observed phenomena: 1) the reflected sound field for certain bounded acoustic beams has a point of null sound intensity which is not present in the incident sound beam and 2) the main portion of the reflected sound field is accompanied by a sound field which becomes weaker as it extends for a considerable distance along the interface, away from the incident beam. This field is called the “trailing sound field.” Assuming an incident beam which is approximately Gaussian, a schematic example of these two phenomena is shown in Fig. 1. have since been reconciled by Bertoni and Tamir [5]. A principle difference between Schoch’s analysis and that of Bertoni and Tamir is that the latter has emphasized the use of complex poles of the plane wave amplitude reflection coeffiThese discrepancies between Schoch’s theory and experiment

Multiple primary neoplasms and the nervous system.

Abstract: Studies of multiple primary neoplasms and their relation to the nervous system should consider two important principles: 1) neoplasms of the nervous system have certain unusual features that distinguish them from tumors occurring elsewhere in the body; and 2) there is good evidence that the various histologic types of nervous system tumors should be regarded as separate diseases. The association of nervous system neoplasms and tumors of other sites may occur in patients with phacomatoses or particular genetic syndromes. In addition, certain nervous system neoplasms may be multicentric in origin. Retinoblastoma and osteosarcoma occur together in the same patient more often than expected by chance, as do meningioma and breast cancer. These relationships are important in that they serve to identify the high risk patient, may provide etiologic clues, may point to the presence of genetic syndromes, and may highlight sites in which subsequent tumors are most likely to develop.

Maturation of the rabbit alveolar macrophage during animal development. III. Phagocytic and bactericidal functions.

Abstract: Phagocytic and bactericidal function of rabbit alveolar macrophages (AMs) lavaged from animals during the course of postnatal maturation was studied. Staphylococcus aureus and a temperature-sensitive mutant of Escherichia coli, which could not replicate at 37 degrees during the functional assays, were employed as test bacteria. Assays of the phagocytic capacity of AMs from rabbits of various age groups revealed no significant differences either in the percentage of AMs which took up bacteria (79-90%) or in the number of bacteria taken up per AM (Table 1). In contrast, bactericidal activity of AMs was found to increase with increasing animal age. No bactericidal activity was detected in AMs from newborn animals (Figs. 1 and 2), whereas AMs from 7-day-old animals exhibited at least a bacteristatic activity against S. aureus (Fig. 1) and AMs from 28-day-old rabbits showed marked bactericidal activity, essentially the same as that of AMs from adult rabbits. Adult AMs killed 75% of the S. aureus and 60% of the E. coli within 120 min (Figs. 1 and 2).

Effects of PGD2 on canine renal function.

Abstract: IN many tissues, especially the mammalian kidney, prostaglandin D2 (PGD2) is a significant product in the metabolism of the bisenoic prostaglandin endoperoxides1,2. PGD2 was originally reported to have negligible biological activity1; but, subsequent workers noted that it produces vascular effects in several species3,4. Although the effects in the kidney of the precursor, arachidonic acid, and other prostaglandins (PGs)5–7 have attracted much interest, the effects of PGD2 have received little attention. Since PGD2 may be an important product of arachidonate metabolism in the kidney8,9, the renal response to an infusion of PGD2 in the dog was examined and compared with the response to an infusion of PGE2. Whereas both PGs produced an increase in renal blood flow, only PGE2 caused a diuresis and natriuresis. This suggests that PGD2 in the kidney is primarily involved in the control of renal haemodynamics, and does not participate in the regulation of fluid and electrolyte excretion.

A comparison of the analgesic effect of oxymorphone by rectal suppository and intramuscular injection in patients with postoperative pain

Abstract: The relative analgesic potency of oxymorphone by rectal suppository and intramuscular injection was evaluated in a double-blind, twin-crossover comparison of graded single doses in 136 patients with postoperative pain. The time-effect curves of the two routes of administration differed substantially; rectal resulted in lower and more delayed peak analgesia and a longer duration of action than intramuscular administration. When both duration and intensity of analgesia are considered (total effect), rectal oxymorphone was 1/10 as potent as the intramuscular form; in peak effect, it was only 1/16 to 1/20 as potent. However, because intramuscular oxymorphone is nine to ten times as potent as intramuscular morphine, 5 to 10 mg oxymorphone by suppository provides analgesia comparable to that provided by the usually used doses of parenteral narcotics. Rectal oxymorphone produced no more, and perhaps somewhat fewer, side effects than doses of intramuscular oxymorphone producing equivalent total analgesic effect. None of the patients objected to the rectal route of analgesic administration. This study demonstrates the feasibility of well-controlled analgesic assays employing the double-dummy technique to compare suppositoreis with oral or parenteral analgesic dosage forms. Our observations also suggest that the rectal route is an acceptable and practical way of administering potent analgesics and is probably being underutilized by physicians in the control of moderate to severe pain.

Hormone requirements for early maintenance of rat granulosa cell cultures.

Abstract: Granulosa cells, obtained from preovulatory follicles of PMS-LH treated immature rats, were cultured as monolayers in 90% medium 199, 10% human male serum and antibiotic. Purified rFSH, rGH, rPRL, hLH or hPL was added separately to the culture medium. Control cultures lacked the above hormones. Progesterone secreted into the culture medium was measured by specific radioimmunoassay and served as an index of luteotrophic stimulation. During a 2 week culture period, rPRL and hPL, but not rFSH, rGH or hLH, brought about complete luteinization as observed by electron microscopy and enhanced progesterone secretion over that of control cultures. The transformation of lamelliform to villiform cristae within mitochondria was the most striking ultrastructural feature indicative of luteotrophic stimulation and progesterone secretion. Rat granulosa cells were also cultured with 0.01, 0.1 and 1.0 μg/ml of rPRL alone or in combination with 0.5 fig rFSH, 0.1 μg hLH or 4.0 ng estradiol (E2)/ml. Cultures maintained with t...

Lymphocyte and Fibroblast Chalones: Some Chemical Properties

Abstract: Experiments with lymphocyte and fibroblast chalones indicate that they are complexed strongly with RNA in tissue extracts; have a molecular weight of less than 10,000 and more than 1,000 daltons, and probably about 5,000 daltons; are strongly cationically charged; and contain mannose and perhaps other carbohydrates.

Significant life experiences in an adult sample.

Abstract: This study sought to focus on the significant life experiences of an adult sample (n = 45, ages 30-60); in particular, stress, traumas, and trauma-resolved experiences were examined and compared to like experiences of an undergraduate sample. The results for the adults revealed that two-thirds of the sample were able to convert traumas into strens, and the ability seemed to be dependent more on the person than the specific event. Success at converting, if it occurred at all, usually occurred while in subjects were in their 20s; once it occurred, subsequent events were more likely to be coped with in a more positive manner. The implications for primary and early secondary prevention are discussed.

A comparison of the analgesic effect of intramuscular nefopam and morphine in patients with postoperative pain.

Abstract: motoneurone excitability and recovery and intramuscular5*6 nefopam have useful heightened stretch and flexion reflexes, analgesic activity. Nefopam is chemically Gasse13 recognized that the drug had an unrelated to any known class of analgesics analgesic effect in his human experimental and is pharmacologically distinct from model for muscle relaxant activity. Subnarcotics, narcotic antagonists, or analsequent well-controlled clinical analgesic gesics such as aspirin with associated antiassays have confirmed that both ~ r a l ~ . ~ and inflammatory and antipyretic a ~ t i v i t y . ~ The present study was undertaken to From the Departments of Pharmacology and Anesthesiology, Georgetown Universi9, schools determine the relative analgesic Potency of Medicine and Dentistry, Washington, D.C. of intramuscular nefopam and morphine Presented in part at the Seventy-eighth Annual in patients with pos~operative pain. JIeeting of the American Society for Clinical Pharmacology and Therapeutics, Dallas, Tex., Varch 1977.1 Material and Methods