Showing papers by "University of Vermont published in 1969"
TL;DR: The most frequent reason for consulting a physician is for him to minimize a severe fear or phobia of a medical procedure, and Psychiatrists tend to see only the more severe phobics, although only a quarter of this group were found to be in treatment.
628 citations
TL;DR: The reciprocity theorem is used to determine the sensitivity of EEG leads to the location and orientation of sources in the brain and the following conclusions are drawn.
Abstract: In this paper, the reciprocity theorem is used to determine the sensitivity of EEG leads to the location and orientation of sources in the brain. Quantitative information used in determining the sensitivity is derived from constant potential plots of a three-concentric-sphere mathematical model of the head with current applied through surface leads (the reciprocal problem), and from an electrolytic tank employing a human skull. Advantages of the reciprocal or lead field approach are outlined and the following conclusions are drawn. 1) Leads placed at the end of a diameter through the center of the brain have a range of sensitivity due to source location of only 3 to 1. 2) For the same electrode placement, sensitivity is maximum to sources oriented parallel to the line of the electrodes regardless of source location. 3) Electrodes spaced 5 cm apart are about ten times more sensitive to proximal cortical sources (by virtue of position) than to sources near the center of the brain.
457 citations
TL;DR: The following three articles report that poly I.poly C, which is of interest as a stimulator of interferon production, has potential side effects.
Abstract: The following three articles report that poly I.poly C, which is of interest as a stimulator of interferon production, has potential side effects.
116 citations
TL;DR: An analysis of variance for a factorial design indicated that only instructions had a significant effect; the reinforcement and interaction factors were not significant.
109 citations
103 citations
TL;DR: Increased metabolic inactivation of warfarin by induction of liver microsomal enzymes is suggested by induction by phenobarbital and glutethimide in conjunction with hypnotic drug treatment.
Abstract: Ten male volunteers received phenobarbital, glutethimide, chloral betaine, and a placebo at bedtime for 3 week periods. Plasma warfarin levels and prothrombin times were determined after a single oral dose of warfarin prior to and immediately following placebo or hypnotic drug treatment. Glutethimide and phenobarbital lowered the plasma warfarin concentration and reduced the half‐life of warfarin by nearly 50 per cent. Chloral betaine had less effect but differed significantly from control values. Phenobarbital and glutethimide interfered with the hypoprothrombinemic effect of warfarin; chloral betaine and placebo did not. The findings suggest increased metabolic inactivation of warfarin by induction of liver microsomal enzymes.
90 citations
TL;DR: The results point to an inefficiency of the imaginative process, and the possibility that behavioral change is enhanced by contact with the feared object.
85 citations
TL;DR: In this article, the fracture energy of cast epoxy resin was measured by a novel method in the presence of various agents, and the crack spontaneously rehealed under heating to above the heat distortion temperature to give a fresh joint of about the same fracture energy as the virgin material.
Abstract: The fracture energy of cast epoxy resin was measured by a novel method in the presence of various agents. The crack spontaneously rehealed under heating to above the heat distortion temperature to give a fresh joint of about the same fracture energy as the virgin material.
73 citations
TL;DR: Kinetic studies with chilled ephippia stored for various times in the dark indicated a diphasic process of photoactivation which has tentatively been interpreted as a light-dependent release of inhibition.
Abstract: The ephippial eggs of Daphnia pulex require light for the initiation of development. The ephippial capsule prevents the completion of development but is not a barrier to an adequate light stimulus. Working with decapsulated eggs, the response to light increased to 100 % within 9 days of storage in the dark and remained at 100% for up to 60 days of storage in the dark. The response was not dependent on drying the ephippia. Ephippia stored in the light did not reach 100% response to illumination when decapsulated, indicating that activation was dependent on prior dark reactions. About 4500 ft-c-min of fluorescent light energy was required for 100% activation. The effective wavelengths were between 350 and 475 mµ with 2 x 106 ergs/cm2 sufficient to initiate nearly 100% development at 410 mµ, the most effective wavelength. Low temperature interfered with photoactivation but not with subsequent development. Chilling the ephippia resulted in an increased light requirement. Kinetic studies with chilled ephippia stored for various times in the dark indicated a diphasic process of photoactivation which has tentatively been interpreted as a light-dependent release of inhibition.
59 citations
55 citations
TL;DR: In this paper, the authors published a preliminary population estimate of 10,000-11,000 persons for Tikal as then known, which was later revised to 49,000 people.
Abstract: In 1965, the author of this paper published a preliminary population estimate of 10,000-11,000 persons for Tikal as then known. Since 1965, mapping and excavation on four radial strips which run up to 12 km. in the four cardinal directions from the center of Tikal have broadened our knowledge of settlement at this site. We now have a good idea of the actual size of Late Classic Tikal, as well as its demographic makeup. This permits a new estimate of its Late Classic population as, conservatively, 49,000 persons. It is suggested that Late Classic Tikal qualifies as an urban center, but of a different sort than the urban centers of Mexico.
TL;DR: It is suggested that the determination of lymphocyte hypersensitivity to autologous tumors may have ultimate prognostic significance.
Abstract: Autologous crude saline extracts of human tumors were incubated with cultures of autologous human lymphocytes, and the degree of stimulation of the lymphocytes was quantitated by tritiated thymidine uptake. While no degree of stimulation was seen in 44 patients, a suggestive elevation was seen in 5 patients and a definite elevation (T:C ratio > 2) in 7 patients. These 7 patients all had tumors with a relatively favorable prognosis, including one patient with malignant melanoma who was undergoing spontaneous regression. It is suggested that the determination of lymphocyte hypersensitivity to autologous tumors may have ultimate prognostic significance.
TL;DR: The sequence of development to be described appears to support the proposal that chloroplast lamellae develop by more than one pathway, and includes disappearance of phytoferritin particles and homogeneous spheroids, decrease in starch content, and appearance of osmiophilic droplets.
Abstract: Chloroplast ontogeny has been examined in 42-day etiolated triploid aspen calltus (Populustremuloides Michx) subjected to two different light conditions White and low-intensity red illumination showed little differences in their stimulatory effects on plastid development, the red light-irradiated plastids developing only slightly more slowly Asynchronous plastid development was noted in both lighting systems Etioplasts contained an interconnected tubular net, phytoferritin aggregates, electron-transparent vesicles which seem to invaginate from the inner plastid membrane, membrane-bound homogeneous spheroids and starch grains Irradiation caused various morphological changes within the proplastids; the tubular complex became transformed into the more ordered prolamellar body-like structure from which radiated membrane-bound sacs filled with electron-dense material These sacs, characterized as thylakoid precursors, were transformed into a thylakoidal system typical of mature chloroplasts This ontogenetic scheme represents an additional pathway for the development of photosynthetic lamellae Other lightinduced changes in the developing plastid include disappearance of phytoferritin particles and homogeneous spheroids, decrease in starch content, and appearance of osmiophilic droplets THE EFFECT of light on the development of chloroplasts is a subject which has been considered in several reviews (Granick, 1961; Goodwin, 1966; Kirk, 1967) The use of tissue culture to study the ontogeny of plastids in higher plants seems worthwhile because it is possible to control the physical and chemical environments and thus regulate differentiation and growth Recently the ultrastructure of developing chloroplasts in several cultured tissues has been studied (Laetsch and Stetler, 1965; Stetler and Laetsch, 1965; Bergmann and Berger, 1966; Israel and Steward, 1967; Sunderland and Wells, 1968) Our investigation describes the ontogeny of chloroplasts in dark-grown aspen tissue culture stimulated by white and low-intensity red-light irradiation The sequence of development to be described appears to support the proposal that chloroplast lamellae develop by more than one pathway MVATERIALS AND METHODS-The triploid aspen callus used in this investigation was initially 1 Received for publication 4 October 1968 Research supported by NSF grants GY-2117 and NSF GB-6066 2 Present address: Tulane University School of Medicine, 1404 Hawthorne, 1300 Canal Street, New Orleans, Louisiana 70112 isolated from internode stem sections of Populus tremuloides Michx It has been maintained in tissue culture for 5 years on a basal medium containing major elements, trace elements, 30 ,ug/ liter glycine, 01 jug/liter thiamine, 05,ug/liter NAA, 2 % (w/v) sucrose, and 10 % (v/v) coconut milk (Mathes, 1964) These cultures were incubated in the dark at 27 C Their only exposure to light during this period was for brief durations, when they were examined for contamination and during aseptic transfer of tissue to fresh petri plates Tissue explants placed on a no sucrose medium (ie, same as above except no sucrose added) were dark-grown in petri plates covered with double thickness heavy duty aluminum foil and were incubated at 27 C for 37 days This tissue was again explanted to a no sucrose medium, and returned to the dark for another 5 days Callus of uniform texture was selected and once again transferred aseptically to no sucrose plates A green safelight consisting of a GE F15 T8 GG fluorescent tube with Cinemoid plastic sheets #5A, #24, #32, and Mylar-W as filters was used The filter system provided a transmission spectrum in the range 525-545 m,4 Parallel series were then prepared with these explants as follows: (1) dark-grown explants, (2) explants placed in the
TL;DR: High concentrations of total plasma cortisol were present, as expected, in both the pregnant and the Enovid-E treated women, but the latter group had a significantly lower per cent filterable cortisol than the nonpregnant group.
Abstract: Unbound plasma cortisol concentrations were determined in nonpregnant, pregnant and Enovid-E treated women. A method is described for the measurement of the unbound fraction using ultrafiltration by centrifugation at 37 C to obtain a filtrate of 1/10 the volume of the plasma sample. Tracer amounts of cortisol-3H were added to determine the per cent of cortisol filterable. Total cortisol concentrations were measured by a fluorometric technique. The mean unbound or ultrafilterable cortisol concentration for the pregnant women was 2.47 μg/100 ml, which is significantly higher (p<.001) than the mean of 1.00 μg/100 ml for the nonpregnant, and 1.31 μg/100 ml for the Enovid-E treated women. High concentrations of total plasma cortisol were present, as expected, in both the pregnant and the Enovid-E treated women, but the latter group had a significantly lower (p<.001) per cent filterable cortisol of 4.3% as compared to 6.3% for the pregnant women, and 7.6% for the nonpregnant women. The implications of ...
TL;DR: A lack of objective, quantifiable personality assessment on the campus drug user is due, in part, to the illegal status of the drugs in question; thus, research in this area has been minimal.
Abstract: Personality characteristics of narcotic addicts and chronic alcoholics have been studied by use of the Minnesota Multiphasic Personality Inventory (MMPI). There is, however, a dearth of personality assessment on the campus drug user. .The studies on campus drug use to date have been concerned with surveys of incidence, basic demographic and academic data. There has also been some focus on types of drugs used and the general patterns of drug use. Some of these studies have included subjective evaluation sections on both drug effects and reasons for drug use. This lack of objective, quantifiable personality assessment is due, in part, to the illegal status of the drugs in question; thus, research in this area has been minimal.
TL;DR: The trypanosomal dihydrofolate reductase activity was detected in extracts of rat-adapted bloodstream forms of Trypanosoma (Trypanozoon) brucei, and the drug sensitivities of the reductases of salivariantrypanosomes were almost identical and, as a group, clearly distinguishable from those of the stercorarian species.
TL;DR: Starvation brings about changes in the enzyme activity pattern similar to those of cortisone-treatment, and hexokinase and glucose-6-phosphate dehydrogenase are also decreased per cell, but only to the same extent as total protein so that there is little change in specific activity.
TL;DR: It is considered that, if results regarding uptake, binding and release of guanethidine are confirmed in vivo, and also found to apply to other pharmacologically active agents, then the eventual loss of a platelet‐bound substance may increase pharmacological action by raising plasma levels.
Abstract: 1. When human blood platelets were incubated aerobically in plasma containing 2 × 10-7 to 10-3M radioactive guanethidine for 10 min to 6 hr, the drug was accumulated against a concentration gradient until concentration ratios (platelet/plasma) of up to 80:1 were obtained.
2. The decline in rate of uptake after 3 hr appeared to result from a decrease in platelet viability, because accumulation was reduced by prolonged incubation before addition of guanethidine.
3. Uptake was energy-dependent because it was inhibited by cold and ouabain.
4. Sodium ions were essential for guanethidine uptake and retention of 5-hydroxytryptamine (5-HT).
5. Accumulation was inhibited by 5-HT, desipramine, cocaine, dexamphetamine, bretylium, tyramine and noradrenaline; bethanidine, p-chlorophenylalanine and (-)-α-methyldopa were inactive.
6. Guanethidine was tightly bound to platelets, only 10% being lost from labelled cells during 60 min incubation in drug-free plasma; but efflux was increased by addition of amphetamine.
7. The binding sites for guanethidine seemed to be different from those for 5-HT since guanethidine accumulation was independent of 5-HT levels, and neither guanethidine uptake or release were affected by reserpine.
8. Guanethidine was not metabolized by platelets or plasma in vitro.
9. We consider that, if our results regarding uptake, binding and release of guanethidine are confirmed in vivo, and also found to apply to other pharmacologically active agents, then the eventual loss of a platelet-bound substance may increase pharmacological action by raising plasma levels.
TL;DR: The hypothesis is advanced that a regulatory mechanism operates in cartilage to coordinately control the levels of glycolytic enzymes and cellular metabolism.
TL;DR: High levels of pyruvate in vitro inhibit lactate formation from labeled glucose by over 90% in normal and cortisone-treated tissue while doubling 14CO2 evolution from glucose-1-14C, suggesting that pyruVate can inhibit glycolysis in cartilage tissue and divert glucose to alternate fates such as the pentose shunt and glycogen synthesis.
TL;DR: In this paper, a mechanical vibrator has been developed to generate the bubbles at controlled sizes and densities, and the measurements suggest that the well-known signals at subharmonics of the fundamental are caused by forced radial oscillation of bubbles that are resonant at the subharmonic frequencies.
TL;DR: This chapter presents experimental techniques for the study of the amphibian lens epithelium, a system upon which it is possible to execute biochemical, histochemical, and microscopic investigations at almost all technical levels in use.
Abstract: Publisher Summary This chapter presents experimental techniques for the study of the amphibian lens epithelium Such techniques can be applied, with slight modifications, to the investigations of lens epithelium in almost any vertebrate organism Many techniques can be applied to investigate the lens epithelium of amphibians (and other animals as well), and newer approaches will be applicable with the passage of time The question of whether such techniques can pave the way for a more acute understanding of cellular activities is important It is a homogeneous group of cells existing in as simple an array as has been found in any multicellular organism Thus, when proliferation is stimulated—for example, by mechanical injury, the trouble related to the possibility of other types of cell complicating the picture dissappear Routine tissue culture should render possible the investigation of almost any question relating to cellular function—for example, work on membrane transport The lens, therefore, emerges as an extraordinarily versatile kind of experimental system, a system upon which it is possible to execute biochemical, histochemical, and microscopic investigations at almost all technical levels in use
TL;DR: It is concluded that the active site of AChE is different from that of the acetylcholine receptor of the intact electroplax of the electric eel.
TL;DR: The order of susceptibility of the aminopteridines (2- > 4-) to oxidation by xanthine oxidase was found to be different from that previously reported by Bergmann and Kwietny 9 for the analogous hydroxypteridine (4- > 2-).
TL;DR: The dihydrofolate reductases in these two flagellates are thus similar in general properties to all such enzymes that have so far been described and some evidence is presented which suggests that C. oncopelti preparations may contain more than one dihyrofolATE reductase.
TL;DR: Studies have been made on several college campuses seeking to determine the incidence and extent of illicit drug use and found that on many college campuses students are known to be involved with drugs.
Abstract: RUG abuse on campus has been widely publicized by the mass media. As a result, studies have been made on several college campuses seeking to determine the incidence and extent of illicit drug use. On many college campuses students are known to be involved with drugs. Evidence of this involvement results from incidence surveys or through midnight raids conducted by law enforcement officials. Other campuses are not identified with drug use. This is not to say that drugs are not available. Drugs are present on these campuses even if the incidence is low.