Showing papers by "Vanderbilt University published in 1981"

The Application and Misapplication of Factor Analysis in Marketing Research

Abstract: The use of factor analysis as a method for examining the dimensional structure of data is contrasted with its frequent misapplication as a tool for identifying clusters and segments. Procedures for...

Characterization of Several Clonal Lines of Cultured Ley dig Tumor Cells: Gonadotropin Receptors and Steroidogenic Responses*

Abstract: Several clonal lines of cultured Leydig tumor cells have been established and characterized in terms of gonadotropin receptors and steroid production. Although freshly isolated cells derived from the M5480P tumor have functional hCG receptors, only two of the five clonal lines established were shown to bind significant quantities of hCG. In these clones, steroid production can be stimulated to the same extent by hCG, cholera toxin, and 8-Br-cAMP. The other three clones bind a small amount of hCG and respond to the hormone with a marginal increase in steroidogenesis. Steroid production, however, is significantly stimulated by cholera toxin or 8-Br-cAMP. A comparison of the steroids produced by freshly isolated cells and two of the clones revealed some changes in the steroidogenic pathway. The most obvious change is an increase in the ability of the cultured cells to synthesize 20α-dihydroprogesterone (20α-hydroxypregn-4-en-3-one). These clonal lines may provide a suitable model system for the study of gona...

Use of a heated superficial hand vein as an alternative site for the measurement of amino acid concentrations and for the study of glucose and alanine kinetics in man

Abstract: Comparisons were made between the artery and a heated superficial hand vein (HSHV) for the measurements of amino acids, lactate, glycerol, free fatty acids, insulin and glucagon and the measurements of glucose and alanine kinetics in man. Normal subjects (n = 8) were studied after an overnight fast (12–14 hr). U-14C-alanine and 3, 3H glucose were administered by a constant infusion and blood was sampled from catheters placed in a radial artery and a superficial dorsal vein of a heated hand (68°C environment), during a control period and a period of a steady state hyperaminoacidemia achieved by a constant infusion of an L-amino acid solution. The blood concentrations of all substrates and hormones measured and the concentrations of cold and radioactive glucose and alanine were comparable in the two vessels during both study periods. In contrast, measurements obtained in a deep forearm vein (DV) showed the concentrations of plasma glucose to be lower (3% in the control period and 5% during the experimental period) and those of plasma alanine to be higher (13% and 5% during control and experimental periods respectively) than the artery or the HSHV. The difference in glucose specific activity between the artery or the HSHV and the DV were however slight but non-significant, while plasma alanine specific activity was significantly lower in the DV as compared to the artery or the HSHV (32% in the control period versus 14% in the experimental period) suggesting a process of exchange of alanine and glucose occuring during the transit of blood across the forearm. As a result blood samples obtained from a DV will overestimate the derived total body glucose and alanine turnover rates. Thus the heated superficial hand vein can adequately replace the artery for the measurements of whole blood amino acids, lactate and glycerol and for plasma FFA, insulin and glucagon; its use can obviate the risks associated with arterial catheterization and can be a suitable site for the measurements of total body glucose and alanine kinetics in man.

Clinical trial in duchenne dystrophy. I. The design of the protocol

Abstract: Therapeutic trials in muscular dystrophy have often been inconclusive. A protocol has been designed which selects patients with Duchenne muscular dystrophy and permits accurate measurement of their status. An integral part of the protocol is a system for checking on the consistency of the data obtained using a computer program.

Composition of plutonic muscovite; genetic implications

Abstract: "Muscovite" (wbite mica) is the most common mineralogical indicator of strongly peraluminous composition in plutonic rocks and, by inference, in their parental magmas. Its presence has been used to constrain depth of crystallization; based upon experimental data, approximately 3 kbar (11 km) is commonly considered the minimum pressure at which primary igneous muscovite can crystallize. Recent suggestions that independent criteria require depths < 1l km for emplacement of some granites with texturally primaryJooking muscovite, so that such mica would in fact be secondary, raise questions about the use of apparently primary muscovite as an indication either of depth or of magma composition. New data from 4l samples representing 16 plutons in North America and Europe are relevant to the paragenesis of muscovite in igneous rocks. Formulas of the analyzed micas are typically about K6.s1Na!.67Fes + o.2oFe2 + 6.n5Mge.roTio.o, Al2.55Sis.10O1o(OH1.ssF0.oz), with very slight trioctahedral substitution (2.00 to 2.04 octahedral cations). Primary- and secondary-looking grains are generally similar, but primary ones are richer in Ti, Na and Al and poorer in Mg and Si. Plutonic muscovite is so far from ideal KAl"Si"Olo[OHl, in composition that it is difficult to evaluate its paragenesis in terms of existing experimental data. The many additional components may enhance the stability field sufficiently to explain occurrences of primary muscovite at surprisingly shallow depths.

Disturbances in prosody. A right-hemisphere contribution to language.

Abstract: In addition to grammar and semantics, prosody constitutes a third element of speech. Modulations of prosody can produce alterations in the meaning and affective tone of spoken language. Previous studies have suggested that right-hemisphere lesions may selectively disrupt a patient's ability to interpret and express the affective component of prosody. On the other hand, this study shows that the effect of right-hemisphere damage on prosody is more widespread. Thus, when discrimination, repetition, and spontaneous production of nonemotional prosody were tested in nine patients with right-sided brain injuries and ten control subjects without brain damage, the patients were found to be significantly worse than the control subjects in their ability to distinguish and express prosodic features that provide phonemic or emphatic information. These results suggest that right-hemisphere damage may affect prosody in a more general manner than was previously assumed.

Reversible inhibition of testicular steroidogenesis and spermatogenesis by a potent gonadotropin-releasing hormone agonist in normal men: an approach toward the development of a male contraceptive.

Abstract: We studied the antifertility effects of a potent gonadotropin-releasing hormone agonist, D-Trp6-Pro9-N-ethylamide-LHRH (LHRHA) in eight normal men, who received daily subcutaneous injections for six to 10 weeks. Plasma testosterone levels fell substantially in all eight. Plasma 17-hydroxyprogesterone and serum estradiol-17β levels decreased concordantly with plasma testosterone. Impotence developed in five men between the sixth and seventh weeks of treatment, with resolution in each case within two weeks of stopping treatment. Serum gonadotropin levels also fell during treatment, briefly rebounding above basal levels when therapy ended. Sperm density and motility fell to a nadir during the seventh to 18th week after therapy. In six subjects sperm levels fell to 6X106 sperm per milliliter or less, and in the other two they decreased 70 and 86 per cent below basal mean values. Sperm density returned to pretreatment levels in all men during the 10-to-14-week recovery period. These results are consis...

Reversible inhibition of testicular steroidogenesis and spermatogenesis by a potent gonadotropin-releasing hormone agonist in normal men: an approach toward the development of a male contraceptive.

Abstract: We studied the antifertility effects of a potent gonadotropin-releasing hormone agonist (LHRHA) D-Trp -Pro -N-ethylamide-LHRH in 8 normal men who received daily subcutaneous injections for 6-10 weeks. Plasma testosterone levels fell substantially in all 8. Plasma 17-hydroxyprogesterone and serum estradiol-17beta levels decreased concordantly with plasma testosterone. Impotence developed in 5 men between the 6th and 7th weeks of treatment with resolution in each case within 2 weeks of cessation of treatment. Serum gonadotropin levels also fell during treatment briefly rebounding above basal levels when therapy ended. Sperm density and motility fell to a nadir during the 7th-18th weeks after therapy. In 6 subjects sperm levels fell to 6x10 sperm/milliliter or less and in the other 2 they decreased 70 and 86% respectively below basal mean values. Sperm density returned to pretreatment levels in all men during the 10-14 weeks of recovery. These results are consistent with LHRHA-induced pituitary "desensitization" but do not exclude a direct inhibitory effect of LHRHA on testicular steroidogenesis and spermatogenesis. (authors)

Pathogenic Mechanisms of Neisseria gonorrhoeae: Observations on Damage to Human Fallopian Tubes in Organ Culture by Gonococci of Colony Type 1 or Type 4

Abstract: The relative virulence of isogenic clones of colony type 1 (T1) (piliated) and colony type 4 (T4) (nonpiliated) gonococci was assessed in organ cultures of human fallopian tubes. The rate of damage to fallopian tube mucosa was determined by measurements of ciliary activity and was correlated with the sequential pathologic events observed by light and electron microscopy. During the first 24 hr of the infection, T1 gonococci attached to and damaged the mucosa more rapidly than did T4 gonococci. This damage was manifested primarily by sloughing of ciliated cells. The observation that gonococci attached almost exclusively to nonciliated cells but damaged primarily ciliated cells suggested that this damage was mediated by one or more toxic factors. After attaching, gonococci entered the nonciliated mucosal cells, increased in numbers inside them, and then invaded the subepithelial tissues. Thus, attachment of gonococci to the fallopian tube mucosa may facilitate effective delivery of one or more gonococcal toxins to target cells in the mucosa and may initiate a process by which gonococci traverse the mucosal barrier.

Further developments in binocular summation

Abstract: This paper reviews experiments that bear on the issue of binocular summation, the superiority of binocular over monocular viewing on various visual tasks covering studies published since the appearance of a previous review of this literature by Blake and Fox (1973). The experiments are grouped into three main categories—those that deal with the specificity of binocular summation (i.e., the extent to which inputs to the two eyes must coincide spatially and temporally), those that study binocular summation on suprathreshold tasks, and those that correlate binocular summation with other aspects of binocular function. The last section of the paper critically reviews several models of binocular summation.

Effectiveness of relaxation training in reducing adverse reactions to cancer chemotherapy

Abstract: Cancer patients who had developed negative conditioned responses to their chemotherapy either did (relaxation training) or did not (no relaxation training) receive progressive muscle relaxation training and guided relaxation imagery instructions immediately before and during their chemotherapy treatments. Physiological (blood pressure and pulse rate) measures of arousal, frequency of vomiting, and patient-reported and nurse-reported indices of negative affect and nausea were collected during pretraining, training and posttraining chemotherapy sessions. Results indicated that during both the training and the posttraining sessions, patients in the relaxation training condition reported feeling less emotionally distressed and nauseated, and showed less physiological arousal following the chemotherapy infusion, than patients in the no relaxation training condition. The attending nurses' observations confirmed the patients' self-reports. No differences were found in frequency of vomiting between conditions. These data clearly suggest that the use of relaxation procedures may be an effective means of reducing several of the adverse side effects of cancer chemotherapy.

Identification of tissue-specific nuclear antigens transferred to nitrocellulose from polyacrylamide gels

Abstract: Nonhistone protein antigens resolved by electrophoresis in sodium dodecyl sulfate were identified immunochemically after being transferred to nitrocellulose. Use of antiserum to dehistonized chromatin from Novikoff hepatoma revealed numerous protein antigens specific to the chromatin of Novikoff hepatoma in comparison to that of normal rat liver.

Autoregressive Estimation of Short Segment Spectra for Computerized EEG Analysis

Abstract: The hypothesis that an electroencephalogram (EEG) can be analyzed by computer using a series of basic descriptive elements of short duration (1-5 s) has prompted the development of methods to extract the best possible features from very short (1 s) time intervals. In this paper, the merits of three alternative methods for estimating spectral features are compared to the fast Fourier transform (FFT). These procedures, based on autoregressive (AR) modeling are: 1) Kalman filtering, 2) the Burg algorithm, and 3) the Yule-Walker (YW) approach. The methods are reportedly able to provide high resolution spectal estimates from short EEG intervals, even in cases where intervals contain less than a ful period of a cyclic waveform. The first method is adaptive, the other two are not. Using Akaike's final prediction error (FPE) criterion, it was demonstrated that a fifth-order filter is sufficient to estimate EEG characteristics in 90 percent of the cases. However, visual inspection of the resulting spectra revealed that the order indicated by the FPE criterion is generally too low and better spectra can be obtained using a tenth-order AR model. The Yule-Walker method resulted in many unstable models and should not be used. Of two remaining methods, i.e., Burg and Kalman, the first provides spectra with peaks having a smaller bandwidth than the Kalman-flter method. Additional experiments with the Burg method revealed that, on the average, the same results were obtained using the FFT.

Theory of positron production in heavy-ion collisions

Abstract: Collisions of very heavy ions at energies close to the Coulomb barrier are discussed as a unique tool to study the behavior of the electron-positron field in the presence of strong extemal electromagnetic fields. To calculate the excitation processes induced by the collision dynamics, a semiclassical model is employed and adapted to describe the field-theoretical many-particle system. An expansion in the adiabatic molecular basis is chosen. Energies and matrix elements are calculated using the monopole approximation. In a supercritical (2, + Z, 2 173) quasiatomic system the 1s level joins the antiparticle continuum and becomes a resonance, rendering the neutral vacuum state unstable. Several methods of treating the corresponding time-dependent problem are discussed. A projectionOperator technique is introduced for a fully dynamical treatment of the resonance. Positron excitation rates in s„, andp,,] states are obtained by numencal solution of the coupled-channel equations and are compared with results from first- plus second-order perturbation theory. Calculations are performed for subcritical and supercritical collisions of Pb-Pb, Pb-U, U-U, and U-Cf. Strong relativistic deformations of the wave functions and the growing contributions from inner-shell bound states lead to a very steep Z dependence of positron production. The results are compared with available data from experiments done at GSI. Correlations between electrons and positrons are briefly discussed.

Attachment of Neisseria meningitidis to Human Mucosal Surfaces: Influence of Pili and Type of Receptor Cell

Abstract: The factors that determine attachment of meningococci predominantly to the mucosa of the nasopharynx rather than to other mucosal surfaces are unknown. Isolates of Neisseria meningitidis from the nasopharynx of carriers and from patients with meningococcal disease were found to be heavily piliated. Isogenic piliated and nonpiliated meningococcal clones were derived from blood and cerebrospinal fluid isolates. Meningococci with pili consistently attached to human nasopharyngeal cells in greater numbers than meningococci without pili. Meningococci treated with trypsin or mechanical shear forces lost pili and exhibited decreased attachment. Attachment of piliated meningococci differed markedly among epithelial cells from different sites. In contrast, nonpiliated meningococci attached equally but in low numbers to all cell types. These data suggest that pili are important mediators of meningococcal attachment. The number and distribution of receptor sites for pili or pili-associated meningococcal ligands differ among human cells and may determine sites of meningococcal colonization.

Postprandial alterations in cardiovascular hemodynamics in autonomic dysfunctional states

Abstract: The effect of food ingestion on supine blood pressure was assessed during 25 studies in 10 subjects with autonomic dysfunction. Profound decreases in both systolic and diastolic pressure occurred. The mean (± standard error of the mean) maximal reduction in systolic blood pressure for the entire group was 49 ± 6 mm Hg (range 22 to 98). The response also occurred in a hypertensive subject after surgical sympathectomy and during alpha adrenergic blockade and hence appears to be a general phenomenon when sympathetic vasoconstrictor function is impaired. The depressor effect of food ingestion was enhanced by propranolol, attenuated by indomethacin and unaffected by diphenhydramine and cimetidine. The phenomenon is thus not explained by histamine release, and can only partly be accounted for by release of arachidonic acid metabolites. Evidence that insulin may play a role in the phenomenon is discussed. Manipulation of diet may prove to be an important adjunct in the management of patients with autonomic dysfunction.

Suppression of resistant ventricular arrhythmias by twice daily dosing with flecainide

Abstract: Flecainide acetate is a new antiarrhythmic agent whose pharmacokinetics have suggested that effective therapy could be achieved with twice daily dosing. The antiarrhythmic and electrocardiographic effects of flecainide were evaluated in 11 patients with chronic ventricular ectopic beats. Nine patients had been resistant or intolerant to at least three antiarrhythmic agents and eight had recurrent nonsustained ventricular tachycardia. The antiarrhythmic efficacy of increasing doses of flecainide was determined by comparison with results during administration of a placebo 2 days before and 3 days after increasing doses of flecainide. All 11 patients had an antiarrhythmic response with a mean 97 percent (range 88 to 100) rate of suppression of ventricular ectopic beats and mean 100 percent rate of suppression of ventricular tachycardia with a mean daily dose of 410 mg (range 200 to 600) of flecainide. Effective therapy was accompanied by lengthening of the P-R (+ 29 percent), QRS (+ 27 percent) and Q-Tc (+ 11 percent) intervals. These changes were not associated with a deterioration in exercise tolerance or a reduction in ejection fraction (0.52 ± 0.08 with placebo, 0.53 ± 0.12 with flecainide) as assessed with two dimensional echocardiography. Increasing doses of flecainide were associated with progressive prolongation of the ventricular ectopic coupling interval before suppression of ventricular ectopic beats. During the placebo washout period after multiple oral doses, the terminal (postabsorptive) phase plasma half-life of flecainide was found to range from 13 to 27 hours (mean 20.3). The minimal effective plasma levels of flecainide (resulting in greater than 90 percent suppression of ventricular etopic beats) ranged from 245 to 980 ng/ml (mean 631). Adverse effects during the inpatient evaluation were limited to blurring of vision in three patients, which resolved with smaller but still effective doses. Suppression of ventricular ectopic beats at a mean rate of 95 percent continued during outpatient therapy. During a mean of 12 months of outpatient follow-up in nine patients, regularly scheduled evaluation of ambulatory arrhythmia frequency continued to document suppression of arrhythmia. Outpatient follow-up occurred monthly for the first 6 months and every 2nd month thereafter. In three patients it was necessary to administer flecainide every 8 hours because blurring of vision occurred at the time of peak plasma levels when the drug was administered every 12 hours. Flecainide was highly effective in suppressing ventricular arrhythmias when administered twice daily.

Changes in plasma drug binding and α1‐acid glycoprotein in mother and newborn infant

Abstract: A number of drugs bind to alpha 1-acid glycoprotein in plasma. To determine whether age-related changes in alpha 1-acid glycoprotein influence drug binding in mother and newborn infant and also the effects of sex, pregnancy, and oral contraceptives on drug binding, the binding of lidocaine, diazepam, propranolol, d-tubocurarine, and metocurine was determined by equilibrium dialysis in 17 men, 16 nonpregnant women, 16 nonpregnant women on oral contraceptives, and 15 mothers and their newborn infants at delivery. The free fraction of d-tubocurarine (p less than 0.05), metocurine (p less than 0.01), propranolol (p less than 0.001), and lidocaine (p less than 0.02) was higher in neonatal blood than in maternal blood, whereas the free fraction of diazepam was less in fetal cord blood than the mother's (p less than 0.02), but higher than that in nonpregnant women (p less than 0.001). The free fractions of diazepam, propranolol, and lidocaine were higher (p less than 0.001) in pregnant women compared with nonpregnant women while the diazepam and lidocaine free fractions were higher (p less than 0.05) in nonpregnant women and oral contraceptives than in women not using them. Alpha 1-acid glycoprotein was lower in the fetus (15.3 +/- 4.7 mg/100 ml) than the mother (49.6 +/- 6.5 mg/100 ml) (p less than 0.002). There was a positive correlation between plasma alpha 1-acid glycoprotein concentrations and the binding ratio (bound/free concentrations) of lidocaine (p less than 0.001; r = 0.623) and propranolol (p less than 0.001); r = 0.652), indicating that it is likely that the elevation of the free fraction of these drugs in the fetus is due in part to lower levels of alpha 1-acid glycoprotein.