Showing papers by "University of North Carolina at Chapel Hill published in 1979"
TL;DR: Results suggest that there is a highly specialized central projection of primary afferent endings which is related to sensory function and not to fiber diameter, and which receives direct input from cutaneous receptors transmitting activity initiated by innocuous stimulation.
Abstract: Single primary afferent myelinated fibers from cutaneous receptors of cat and monkey were functionally identified by recording from the spinal cord with micropipettes filled with horseradish peroxidase (HRP). Relatively slowly conducting fibers (less than 40 m/sec) from high threshold mechanoreceptors (mechanical nociceptors) and two types of low threshold mechanoreceptor (D-hair and field) were selected for staining. Iontophoresis of the HRP and subsequent histochemical reaction stained the axons recorded from and their collaterals, including terminations, for several millimeters. The termination patterns in the two species proved essentially identical. Ipsilaterally, the mechanical nociceptor fibers terminated principally in the dorsal horn's marginal zone and in the ventral parts of the nucleus proprius (lamina V in the cat). Some of these nociceptors also had terminals in the midline just dorsal to the central canal, contralaterally in the marginal zone, and at the base of the opposite nucleus proprius. In contrast, the D-hair primary afferent axons terminated in the dorsal part of the nucleus proprius overlapping into the innermost portion of the substantia gelatinosa. The field receptor fibers terminated predominantly in the middle part of the nucleus proprius. These results suggest that there is a highly specialized central projection of primary afferent endings which is related to sensory function and not to fiber diameter. The marginal zone and most dorsal parts of the substantia gelatinosa receive direct projections from cutaneous nociceptors but do not have direct input from cutaneous receptors transmitting activity initiated by innocuous stimulation.
783 citations
TL;DR: Cell types that contain receptors for 1,25-dihydroxyvitamin D3 or metabolites of this compound both in known or hypothesized target tissues and in tissues that were previously unknown to participate in vitamin D3 metabolism are revealed.
Abstract: After mature rats that had been fed on a vitamin D3-deficient diet were injected with tritium-labeled 1,25-dihydroxyvitamin D3, radioactivity became concentrated in nuclei of luminal and cryptal epithelium of the duodenum, jejunum, ileum, and colon; in nuclei of the epithelium of kidney distal tubules including the macula densa, and in podocytes of glomeruli; in nuclei of the epidermis including outer hairshafts and sebaceous glands; and in nuclei of certain cells of the stomach, anterior and posterior pituitary, and parathyroid. These results reveal cell types that contain receptors for 1,25-dihydroxyvitamin D3 or metabolites of this compound both in known or hypothesized target tissues and in tissues that were previously unknown to participate in vitamin D3 metabolism.
718 citations
TL;DR: Immunity induced by a single infection had no demonstrable effect on illness associated with reinfection one year later; however, a considerable reduction in severity occurred with the third infection, suggesting that amelioration of illness--rather than prevention of infection--may be a realistic goal for immunoprophylaxis.
Abstract: To better understand acquired immunity to respiratory-syncytial-virus infections, we analyzed data from a 10-year study of respiratory illness in normal children who were followed longitudinally from early infancy. Immunity was measured in terms of failure to become infected or reduction in severity of clinical illness upon reinfection. Outbreaks of infections occurred seven times over the 10-year-period. During epidemics the attack rate for first infection was 98 per cent. The rate for second infections (75 per cent) was modestly reduced (P less than 0.001); that for third infections was 65 per cent. Age and history of infection both influenced illness. Immunity induced by a single infection had no demonstrable effect on illness associated with reinfection one year later; however, a considerable reduction in severity occurred with the third infection. These observations suggest that amelioration of illness--rather than prevention of infection--may be a realistic goal for immunoprophylaxis.
686 citations
TL;DR: In this article, the authors present conditions générales d'utilisation (http://www.numdam.org/conditions), i.e., Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.
Abstract: © Publications mathématiques de l’I.H.É.S., 1979, tous droits réservés. L’accès aux archives de la revue « Publications mathématiques de l’I.H.É.S. » (http:// www.ihes.fr/IHES/Publications/Publications.html) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.
566 citations
TL;DR: In this paper, the duality between stochastic frontier production and cost funstions, under the assumtions of exact cost minimization (tecchnical inefficiency only) and of inexact cost minimisation (technical and allocative inefficiency).
552 citations
TL;DR: Characterization of the TK-/- mutants suggests that two mutagenic mechanisms contribute to their final yield, and is consistent with the induction of slow-growing specific locus mutants by a chromosomal mechanism and their subsequent dilution during this long expression time.
Abstract: The current status of the L5178Y/TK+/- leads to TK-/- mouse-lymphoma mutagenicity assay is described. Dose-survival-mutagenic response data are shown for 43 chemicals. Mutagenicity and cytotoxicity in the presence or absence of non-induced and/or Aroclor-induced rat-liver S-9 are compared for most of these chemicals, 25 of these for which usuable carcinogenicity data exist have been used to construct an approximately linear relationship between oncogenic potency in vivo and mutagenic potency in this system in vitro; linearity between these two endpoints extends over a greater than 100,000-fold range in potencies. Several carcinogens which are negative or difficult to detect in the standard Ames assay are mutagenic in this mammalian cell system. These include natulan, sodium saccharin (lot S-1022), p,p'-DDE (metabolite of DDT), dimethylnitrosamine, diethylnitrosamine and diethylstilbestrol. Characterization of the TK-/- mutants suggests that two mutagenic mechanisms contribute to their final yield. Large-colony TK-/- mutants probably represent point or gene mutations affecting the TK locus. In addition, a class of small-colony TK(/- mutants are described and characterized as being heritably growth-deficient; this and other properties suggest that these small-colony TK-/- mutants originate by a heritable and viable chromosomal aberration. Most carcinogens and mutagens tested produce both classes of TK-/- mutants in this system; the relative proportions of small- and large-colony mutants are both mutagen- and dose-dependent. Comparative studies have been done at the rapidly-expressing TK locus and the slowly-expressing HGPRT locus in these cells. Several carcinogens detected at the TK locus are non- or very weakly mutagenic at the HGPRT locus. This findings is consistent with the induction of slow-growing specific locus mutants by a chromosomal mechanism and their subsequent dilution during this long expression time.
521 citations
TL;DR: It is proved that neural crest cells from other regions of the head can mimic the development of periocular crest cells, and proves that the environment through which these cells migrate plays an essential role in establishing the timing and spatial patterns of their movement.
471 citations
TL;DR: Primary afferent fibers in the lumbar, sacral, and caudal spinal segments of several mammals (rat, cat, monkey) were stained by applying horseradish peroxidase to the proximal part of cut dorsal rootlets and reacting the tissue histochemically after several hours of survival.
Abstract: Primary afferent fibers in the lumbar, sacral, and caudal spinal segments of several mammals (rat, cat, monkey) were stained by applying horseradish peroxidase to the proximal part of cut dorsal rootlets and reacting the tissue histochemically after several hours of survival. The stained fibers' pattern of termination in the dorsal horn was similar in all three species, with many bouton-like enlargements in the ipsilateral marginal zone, substantia gelatinosa, and nucleus proprius, as well as a few projections at each level to the dorsal commissure and contralaterally to the ventral border of the nucleus proprius. Partial lesions of dorsal rootlets in monkey revealed that the thin fibers comprising the lateral division end principally in the marginal zone and substantial gelatinosa, while the thick fibers of the medial division terminate in the nucleus proprius and deeper regions, contributing little to the substantia gelatinosa and marginal zone. On the basis of the termination patterns observed for whole and partly sectioned rootlets, the superficial dorsal horn can be divided into at least four regions. (1) The marginal zone (lamina I of cat) appears to receive terminations from intermediate (smaller myelinated) fibers; (2) the outer substantia gelatinosa (outer lamina II) receives many terminations from the very finest afferent fibers; (3) the inner substantia gelatinosa (inner lamina II) receives endings from some of the finest fibers and also from intermediate (smaller myelinated) fibers; and (4) the superficial part of the nucleus proprius (lamina III) receives endings from intermediate and large diameter dorsal root fibers.
467 citations
TL;DR: In this article, rate constants for electron-transfer quenching of Ru(bpy)32+* (bpy is 2,2'-bipyridine) by a series of organic quenchers have been determined in acetonitrile (μ = 0.77 ± 0.1 M) at 22 ± 2 °C.
Abstract: Rate constants for electron-transfer quenching of Ru(bpy)32+* (bpy is 2,2'-bipyridine) by a series of organic quenchers have been determined in acetonitrile (μ = 0.1 M) at 22 ± 2 °C. The reactions studied were based on three different series of structurally related quenchers having varying redox potentials. They include oxidative quenching both by a series of nitroaromatics (ArNCh) and by a series of bipyridinium ions (P2+) and reductive quenching by a series of aromatic amines (R^NAr). After corrections for diffusional effects, the quenching rate constant (kq') data fall into two classes both of which can be treated successfully using Marcus-Hush theory. For case 1, which includes the data for oxidative quenching by P2+ and reductive quenching by RaNAr, RT In kq varies as AG21/2 where | AGasI « /2. AG23 is the free energy change for electrontransfer quenching within an association complex between the quencher and excited state and is the vibrational contribution to the activation barrier to electron transfer. The experimental data are also consistent with Marcus-Hush theory over a more extended range in AG22 where the free energy dependence includes a quadratic term. For case II, which includes quenching by several of the nitroaromatics, RT In kq varies as AG23 and evidence is obtained from the remainder of the data for a transition in behavior from case 11 to case I. The microscopic distinction between the two cases lies in competitive electron transfer to give either groundor excited-state products following the electron-transfer quenching step. For case II, back-electron transfer (A32) to give the excited state, e.g., Ru(bpy)33+,ArNC>2— Ru(bpy)32+*,ArN02, is more rapid than electron transfer to give the ground state (A30), e.g., Ru(bpy)33+,ArN02~ Ru(bpy)32+,ArN02· For case I, electron transfer to give the ground state is more rapid. The different behaviors are understandable using electron-transfer theory when account is taken of the fact that k30 is a radiationless decay rate constant, and the electron-transfer process involved occurs in the abnormal free-energy region where — AG22 > . An appropriate kinetic treatment of the quenching rate data allows estimates to be made of redox potentials for couples involving the excited state. Formal reduction potentials in CH3CN (μ = 0.1 M) at 22 ± 2 °C are £(RuB33+-/2+*) = —0.81 ± 0.07 V and £(RuB32+‘/+) = +0.77 ± 0.07 V. Comparisons between groundand excited-state potentials show that the oxidizing and reducing properties of the Ru(bpyb2+ system are enhanced in the excited state by the excited-state energy, that the excited state is unstable with respect to disproportionation into Ru(bpy)3+ and Ru(bpy)33+, and that the excited state is thermodynamically capable of both oxidizing and reducing water at pH 7. A comparison between the estimated 0-0 energy of the excited state and the energy of emission suggests that there may be only slight differences in vibrational structure between the ground and excited states.
422 citations
01 Jan 1979
TL;DR: A review of experiments in which large, epibenthic predators are excluded from soft-sediment marine benthic communities in unvegetated portions of estuaries and lagoons and a comparison of grassbeds, where predators on the infauna are less effective, demonstrate that such soft- sediment systems, when freed from predation, usually exhibit an increase in total density, a increase in species richness, and no tendency toward competitive exclusion by some dominant species as mentioned in this paper.
Abstract: A review of experiments in which large, epibenthic predators are excluded from soft-sediment marine benthic communities in unvegetated portions of estuaries and lagoons and a comparison of unvegetated areas with nearby grassbeds, where predators on the infauna are less effective, demonstrate that such soft- sediment systems, when freed from predation, usually exhibit 1) an increase in total density, 2) an increase in species richness, and 3) no tendency toward competitive exclusion by some dominant species. The currently accepted model of community organization, developed from experimental work in marine rocky intertidal communities, would predict that significant simplification of the community should occur as a consequence of intense competition in such a system where density had increased substantially following the removal of predators.
364 citations
TL;DR: The responses of postsynaptic units to graded electrical volleys in intact dorsal roots and to physiological stimulation revealed that the peripheral excitatory input to neurons of the region is dominated by slowly conducting afferent fibers.
Abstract: Functional characteristics of spinal neurons located in the marginal zone (lamina I) and substantia gelatinosa (lamina II) were compared to their structural features by intracellularly staining the source of unitary potentials with horseradish peroxidase (HRP) in unanesthetized, spinal cats. The responses of postsynaptic units to graded electrical volleys in intact dorsal roots and to physiological stimulation revealed that the peripheral excitatory input to neurons of the region is dominated by slowly conducting afferent fibers; often, the input to a given element is largely from a particular class of receptors. One type commonly seen received its principal peripheral excitation from low threshold mechanoreceptors with Aδ or C afferent fibers. Mechanoreceptive elements often exhibited a marked, prolonged habituation and many were not excited by afferent volleys. Other units were predominantly excited by nociceptors with myelinated or unmyelinated fibers, or by thermoreceptors with unmyelinated fibers. A few units (principally the thermoreceptive) showed substantial ongoing activity which was modulated by sensory stimulation, but most had little or none.
The HRP staining revealed neuronal morphology in fine detail. No relationship between neuronal configuration and physiological response was discerned. Soma location was not always linked to afferent input, although the cell bodies of nonciceptive and thermoreceptive neurons tended to be in lamina I or outer lamina II (SGo) while those of the inocuous mechanoreceptive neurons tended to be in inner lamina II (SGi). The locus of a neuron's major dendritic arborization was more closely related to the source(s) of peripheral excitation. Cells excited by nociceptors with myelinated fibers had major dendritic projections in the marginal zone. Cells excited by nociceptors or thermoreceptors with unmyelinated fibers had important dendritic branching in the SGo. Innocuous mechanoreceptive neurons had primary dendritic aranching in the SGo. Innocuous mechanoreceptive neurons had primary dendritic arborization in the SGi when the input derived from unmyelinated fibers, or in the SGi and extending into the outer nucleus proprius (lamina III) when the afferent drive came from Aδ fibers.
These findings support the concept that laminae I and II constitute a major termination region for thin primary afferent fibers, myelinated fibers from nociceptors ending principally in lamina I and unmyelinated fibers from nociceptors, thermoreceptors, and mechanoreceptors terminating predominantly in lamina II. Substantial integrative and distributive functions can be expected of such an afferent termination zone.
TL;DR: Measurement of somatomedin-C appears to provide a reliable means for confirming the diagnosis of acromegaly and of clinical disease activity than measurement of growth hormone concentrations.
Abstract: We measured serum concentrations of somatomedin-C by radioimmunoassay in 57 acromegalic patients and compared them with various indicators of disease activity. The mean fasting somatomedin-C concentration was 6.8 U per milliliter (range, 2.6 to 21.7) for the acromegalics and 0.67 U per milliliter (range, 0.31 to 1.4) for 48 normal, fasting adults. The somatomedin-C concentration correlated significantly with: heel-pad thickness (r = 0.73), fasting glucose (r = 0.74), and one-hour postprandial glucose (r = 0.77). In contrast, "glucose-suppressed" growth hormone correlated weakly (r = 0.34, 0.36, 0.34) with these clinical indexes of severity. Fasting growth hormone levels showed no correlation (r = 0.14). Five active acromegalics had "normal" growth hormone levels after glucose suppression, but they had elevated somatomedin-C. In 15 patients studied one year after treatment, changes in somatomedin-C concentrations paralleled the degree of clinical improvement. Measurement of somatomedin-C appears to provide a reliable means for confirming the diagnosis of acromegaly and of clinical disease activity than measurement of growth hormone concentrations.
TL;DR: In this paper, an energy corrected sudden (ECS) approximation is derived by explicitly incorporating both the internal energy level spacing and the finite collision duration into the sudden S-matrix.
Abstract: Two new theoretical developments are presented in this article. First an energy corrected sudden (ECS) approximation is derived by explicitly incorporating both the internal energy level spacing and the finite collision duration into the sudden S‐matrix. An application of this ECS approximation to the calculation of rotationally inelastic cross sections is shown to yield accurate results for the H+–CN system. Second, a quantum number and energy scaling relationship for nonreactive S‐matrix elements is derived based on the ECS method. A few detailed illustrations are presented and scaling predictions are compared to exact results for R–T, V–T, and V–R, T processes in various atom–molecule systems. The agreement is uniformly very good — even when the sudden approximation is inaccurate. An important result occurs in the analysis of V–T processes: the effects of anharmonic wave functions (coupling) and decreasing vibrational energy gaps (energetics) are separated. Each factor makes significant contributions to the deviation of the anharmonic from the harmonic scaling relationship.
TL;DR: It is concluded that radiation therapy in commonly employed dosages for malignant gliomas carries a risk of injury to surrounding cerebral tissues.
Abstract: To investigate the pathologic consequences of therapeutic radiation, this morphologic study evaluated the brains of 25 patients with intracranial gliomas treated both with and without this form of therapy. Although beneficial effects such as the retardation of tumor growth were evident in these studies, among the seventeen patients who received from 5000--6000 rads for malignant gliomas, four developed "late delayed" radiation necrosis. The strong predilection of this tissue response for the white matter adjacent to the neoplasm suggests a local sensitivity which may have been engendered or enhanced by cerebral edema. A fifth case disclosed focal demyelination in the mid-brain suggesting "early delayed" radiation necrosis, and an additional case had distinctive foci of necrosis within the brain stem. Changes of diffuse cerebral edema were noted in many of the radiated brains. It is concluded that radiation therapy in commonly employed dosages for malignant gliomas carries a risk of injury to surrounding cerebral tissues.
TL;DR: The most common cause of WARI in children under 5 years of age was RSV whereas Mycoplasma pneumoniae was the most frequent isolate from school age children with wheezing illness, and patient age influenced the pattern of recovery of these agents.
TL;DR: Thirteen leukemic patients with disease refractory to conventional chemotherapy were treated with 1.0 to 7.5 g/m2 of Cytosine Arabinoside (Ara‐C) over 29 drug cycles, and three or four dose cycles were given at 2‐ to 30‐day intervals to establish single dose tolerance.
Abstract: Thirteen leukemic patients with disease refractory to conventional chemotherapy were treated with 1.0 to 7.5 g/m2 of Cytosine Arabinoside (Ara-C) over 29 drug cycles. Drug infusions were spaced at 12-hour intervals; a maximum of four doses was administered over 36 hours. After single dose tolerance had been established, three or four dose cycles were given at 2- to 30-day intervals. There were three partial remissions (PR) and one complete remission (CR) in a treatment group of four patients with AML, five with ALL, two with lymphoma converted to leukemic phase, one CML in blast crisis, and one promyelocytic leukemia. Five of the patients were septic and considered terminally ill at the time of treatment. All other patients had evidence of drug responsiveness. The nadir of the white count occurred from 3 to 12 days after treatment, with subsequent recovery of the peripheral granulocyte count between days 12 and 28. Toxicity included nausea and vomiting (GI symptoms) in twelve patients, central nervous system (CNS) disturbances in eight patients, one episode of inappropriate antidiuretic hormone syndromes (SIADH), one of hyperuricemia, and fever in eleven patients. There was no evidence of hepatic or renal dysfunction. These high doses of Ara-C appear useful for treatment of patients with refractory leukemia. Hospitalization is brief and toxicity acceptable.
TL;DR: In this article, the authors attributed the forbidden triplet-to-singlet transition of the center of the $F$ center to the lifetime of the 3 eV emission band.
Abstract: An $F$-center emission band (3 eV) has been observed in subtractively colored ${\mathrm{Al}}_{2}$${\mathrm{O}}_{3}$ crystals upon exciting with $F$ light (6.1 eV). The lifetime of the 3 eV luminescence is 36 \ifmmode\pm\else\textpm\fi{} 4 msec. We attribute this long lifetime to the forbidden triplet-to-singlet transition of the $F$ center. The $F\ensuremath{\leftrightarrow}{F}^{+}$ conversion can be shown by studying the $F$ and ${F}^{+}$ emission bands in these crystals.
TL;DR: In this article, an obstruction theory is developed to decide when an isomorphism of rational cohomology can be realized by a rational homotopy equivalence (either between rationally nilpotent spaces, or between commutative graded differential algebras).
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01 Jan 1979TL;DR: In this article, a general family of weighted-rankings test statistics for comparing two or more treatments is presented, which are simple to compute, are strictly distribution free, and have asymptotic chi-squared distributions.
Abstract: The standard nonparametric procedures for testing the hypothesis of no treatment effects in a complete blocks experiment depend entirely on the within-block rankings. If block effects are assumed additive, however, then between-block information may be recovered by weighting these rankings according to their credibility with respect to treatment ordering. (For the special case of only two treatments, the sign test exemplifies use of unweighted rankings and the signed-rank test weighted.) A general family of weighted-rankings test statistics for comparing two or more treatments is presented. They are simple to compute, are strictly distribution free, and have asymptotic chi-squared distributions.
TL;DR: It is concluded that the decrease in serum T3 concentrations during fasting spares muscle protein and is accompanied by a lower set point of TSH secretion, which remains sensitive to changes in serum thyroid hormone concentrations.
Abstract: To determine the implication of decreased T3 production during fasting, seven normal men were fasted for 80 hours on two occasions; they received 5 microgram of T3 every three hours durnig the second fast. The mean serum T3 concentration declined during the control fast from 120 to 73 ng per deciliter (P less than 0.01), but remained slightly above base-line values during the T3 fast. Mean serum T4 concentrations did not change, and mean serum rT3 concentrations increased, during both fasts. The peak serum TSH increment after TRH was 11.1 micromicron per milliliter before fasting, 8.9 (not significant) after the control fast and 2.2 (P less than 0.01) after the T3 fast. Urea excretion was 9.1 per cent higher during the T3 fast; there were no differences in the changes in blood glucose, plasma fatty acids or other substrates during the two fasts. Pretreatment with potassium iodide lowered serum T4 concentrations and increased the serum TSH response to TRH after fasting. We conclude that the decrease in serum T3 concentrations during fasting spares muscle protein. Fasting is accompanied by a lower set point of TSH secretion, which remains sensitive to changes in serum thyroid hormone concentrations.
TL;DR: The projections of the spinothalamic tract in the macaque monkey have been reinvestigated using the Wiitanen modification of the Fink‐Heimer technique and it was found that the spin hypothalamic tract ascends outside the medial lemniscus, enters the thalamus just dorsal to this structure, and terminates in the posterior, intralaminar and ventral regions.
Abstract: The projections of the spinothalamic tract in the macaque monkey have been reinvestigated using the Wiitanen modification of the Fink-Heimer technique. In agreement with previous studies in the monkey (mehler, Bowsher, Kerr) it was found that the spinothalamic tract ascends outside the medial lemniscus, enters the thalamus just dorsal to this structure, and terminates in the posterior, intralaminar and ventral regions, as well as in the zona incerta. The posteromedial nucleus (POm) receives a dense spinothalamic projection medially and ventromedially; elsewhere in the POm the projection is more scattered. The fibers to the intralaminar region terminate in the nucleus centralis lateralis (CL) with a distinct pattern of the distribution. The nucleus centralis medialis (CeM) has a minute projection. There was no evidence for somatotopic organization in the projections to the POm or to the intralaminar region. The distribution of the terminal degeneration in the ventral region was more complex. Although present in the whole nucleus ventralis posterolateralis (VPL), the degeneration was unevenly distributed and also extended beyond the VPL. So-called clusters of dense degeneration lay in the outskirts of the forelimb and hindlimb representation areas, namely at its ventral, ventrolateral, dorsolateral, and medial borders. Centrally the degeneration was scattered. Thus, most of the VPL receives only a sparse spinothalamic projection, but a small portion contains dense networks of terminal spinal fibers. A somatotopic pattern was evident, for after low thoracic lesions most of the medial VPL lacked degeneration. Spinothalamic fibers pass beyond the VPL to terminate in a zone of transition (nucleus ventralis intermedius of V.im of Hassler, '59; Mehler, '71) between the rostral pole of the VPL and the nucleus ventralis lateralis (VL). This zone also reportedly receives cerebellar and vestibular afferent fibers. Observations suggesting that the evolution of the spinothalamic tract and the spino-cervico-thalamic pathway in carnivores and primates may be linked are discussed. The spinothalamic clusters in the monkey's VPL appear to be homologous to much of the cervicothalamic tract projection to the VPL in the cat.
TL;DR: Electropositive filters appear to offer distinct advantages over conventional negatively charged filters for concentrating enteric viruses from water, and their behavior tends to confirm the importance of electrostatic forces in virus recovery from water by microporous filter adsorption-elution methods.
Abstract: Microporous filters that are more electropositive than the negatively charged filters currently used for virus concentrations from water by filter adsorption-elution methods were evaluated for poliovirus recovery from tap water. Zeta Plus filters composed of diatomaceous earth-cellulose-"charge-modified" resin mixtures and having a net positive charge of up to pH 5 to 6 efficiently adsorbed poliovirus from tap water at ambient pH levels 7.0 to 7.5 without added multivalent cation salts. The adsorbed virus were eluted with glycine-NaOH, pH 9.5 to 11.5. Electropositive asbestos-cellulose filters efficiently adsorbed poliovirus from tap water without added multivalent cation salts between pH 3.5 and 9.0, and the absorbed viruses could be eluted with 3% beef extract, pH 9, but not with pH 9.5 to 11.5 glycine-NaOH. Under water quality conditions in which poliovirus recoveries from large volumes of water were less than 5% with conventional negatively charged filters and standard methods, recoveries with Zeta Plus filters averaged 64 and 22.5% for one- and two-stage concentration procedures, respectively. Electropositive filters appear to offer distinct advantages over conventional negatively charged filters for concentrating enteric viruses from water, and their behavior tends to confirm the importance of electrostatic forces in virus recovery from water by microporous filter adsorption-elution methods.
TL;DR: Two sites of 1 alpha-hydroxylation of 25OHD3, one renal and the other extra-renal, either fetoplacental or maternal, may exist in the pregnant, vitamin D-deficient rat.
Abstract: The kidneys are thought to be the only organs capable of 1 alpha-hydroxylation of vitamin D and its metabolites. We have examined the in vivo conversion of 3H-(25,26)-25-hydroxyvitamin D3(25OHD3) to 3H-(25,26)-1 alpha,25-dihydroxyvitamin D3 [1 alpha,25(OH)2D3] in vitamin D-deficient, pregnant and nonpregnant rats. As expected, nephrectomy of nonpregnant, vitamin D-deficient rats prevented the conversion of 25OHD3 to 1 alpha,25(OH)2D3. In contrast, nephrectomy of pregnant, vitamin D-deficient rats reduced but did not abolish the formation of 1 alpha,25(OH)2D3 from its precursor. The identity of the radioactive metabolite formed from 3H-25OHD3 which circulated in nephrectomized, pregnant rats was established as 1 alpha,25(OH)2D3 by comigration with synthetic 1 alpha,25(OH)2D3 on high-pressure liquid chromatography. The simultaneous absence of 1 alpha,25(OH)2D3 in the fetal kidneys indicated that the site of 1 alpha-hydroxylation after nephrectomy of the pregnant rat was probably extra-renal in origin. Two sites of 1 alpha-hydroxylation of 25OHD3, one renal and the other extra-renal, either fetoplacental or maternal, may exist in the pregnant, vitamin D-deficient rat.
TL;DR: The export of organic carbon per unit runoff from five small, eastern North Carolina watersheds with considerable swamp drainage was severalfold higher than the export rates from upland watersheds reported in the literature as mentioned in this paper.
Abstract: Export of organic carbon per unit runoff from five small, eastern North Carolina watersheds with considerable swamp drainage was severalfold higher than the export rates from upland watersheds reported in the literature This reflects the higher concentrations of organic carbon, especially dissolved forms, in swamp waters and is probably attributable to increased contact time between water and organic debris as well as to concentration effects of high evapotranspiration in swamps
TL;DR: Data demonstrate that NT and beta-endorphin, two endogenous brain peptides, are potent in inducing hypothermia and in producing an antinociceptive state.
Abstract: The antinociceptive and hypothermic effects of intracisternal administration of 11 endogenous neuropeptides and morphine were evaluated in mice. Of the substances tested, only neurotensin (NT) and beta-endorphin exerted significant antinociceptive and hypothermic effects; NT was the most potent in inducing hypothermia whereas beta-endorphin was the most potent antinociceptive agent via this route of administration. Both NT, and beta-endorphin were, on a molar basis, considerably more potent antinociceptive agents than morphine, [Met]enkephalin, or [Leu]enkephalin. NT-induced analgesia and hypothermia both were significantly dose-dependent. Substance P was found to produce significant hyperalgesia and hyperthermia. Bombesin produced a significant hypothermic effect, whereas somatostatin and luteinizing hormone-releasing hormone (luliberin) produced hyperthermia. None of the other peptides studies [bradykinin, thyrotropin-releasing factor (thyroliberin), melanocyte-stimulating hormone release-inhibiting factor (melanostatin), somatostatin, [Met]enkephalin, and [Leu]enkephalin] produced any significant alterations in colonic temperature or response to a noxious stimulus with the doses tested. These data demonstrate that NT and beta-endorphin, two endogenous brain peptides, are potent in inducing hypothermia and in producing an antinociceptive state.
TL;DR: It is concluded that the enhanced RVR in 12-wk-old SHR is primarily a consequence of a physiological, autoregulatory response of afferent arteriolar resistance to the elevated arterial pressure.
Abstract: Renal and nephron hemodynamics were compared between anesthetized, nondiuretic, spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Although the mean arterial pressure was higher in SHR than in WKY, 158 VS. 114 mmHg, glomerular filtration rate (GFR) and renal blood flow (RBF) were similar in both groups. So were intrarenal hydrostatic pressures, single nephron GFR (SNGFR), and single nephron blood flow (SNBF). Accordingly, the increased renal vascular resistance (RVR) in SHR was due to predominant preglomerular vasoconstriction. In a second group of SHR, SHR-AC, the femoral arterial pressure was reduced acutely to 114 mmHg by means of aortic constriction above the renal arteries. The mean values for GFR, RBF, SNGFR, SNBF, and intrarenal hydrostatic pressures resembled those in SHR, whereas RVR was less in SHR-AC. These autoregulatory adjustments of RVR were again largely limited to the preglomerular vasculature. Efferent arteriolar resistance was similar in all three groups. We conclude that the enhanced RVR in 12-wk-old SHR is primarily a consequence of a physiological, autoregulatory response of afferent arteriolar resistance to the elevated arterial pressure. Further, RVR in SHR is not fixed and constant but responds appropriately to reductions in renal perfusion pressure.
TL;DR: The absolute affinities of amino acid side chains for solvent water closely match their relative distributions between the surface and the interior of native proteins and are associated with a remarkable bias in the genetic code.
Abstract: The absolute affinities of amino acid side chains for solvent water closely match their relative distributions between the surface and the interior of native proteins and are associated with a remarkable bias in the genetic code.
TL;DR: The sesquiterpene lactones were marginally effective against induced pleurisy and the delayed hypersensitivity was suppressed by these agents whereas immunoglobulin synthesis was slightly stimulated.
TL;DR: It is suggested that early diastolicleft ventricular relaxation is impaired in congestive cardiomyopathy and that this defect occurs in association with a decrease in left ventricular diastolics compliance.
Abstract: Elevated ventricular diastolic pressures are characteristic of congestive heart failure, and are generally thought to result from reduced ventricular emptying in systole. To determine whether other factors might contribute to the increased diastolic pressures within the left ventricle in con- gestive heart failure, we examined parameters of both left ventricular relaxation rate and diastolic compliance in eight patients with chronic congestive heart failure due to cardiomyopathy, and compared them with similar observations in a control population. Combined recordings of simultaneous left ventricular pressure and echocardiogram were obtained in each case. Left ventricular relaxation rate was assessed by measurement of the maximum rate of left ventricular pressure decline (peak negative dP/dt) and the mean velocity of circumferential fibre lengthening (VCFL) in early diastole. Both of these parameters were significantly decreased in congestive cardiomyopathy patients compared with controls (peak negative dP/dt: 138 ± 15 kPa·s−1 (1037 ± 115 mmHg·s1) versus 347 ± 22 kPa·s−1 (2607 ± 120 mmHg·s−1) for controls, P<0.0005; VCFL; 0.9 ± 0.1 s−l in congestive cardiomyopathy versus 1.3 ± 0.1 s−1 in controls, P<0.01). Left ventricular diastolic distensibility, ΔD/ΔP, and normalised distensibility, (ΔD/ΔP)/D, were significantly decreased in cardiomyopathy subjects as compared with controls (ΔD/ΔP=0.165 ± 0.03 cm (dimension) kPa−1 [0.02 ± 0.004 cm (dimension)·mmHg−1) compared with 1.28 ± 0.23cm (dimension)·kPa−1 [0.17 ± 0.03 cm (dimension)·mmHg−1] for controls, P<0.0005; (ΔD/ΔP)/D=25.6 ± 3.8 kPa−1 × 10 −3 (3.4 ± 0.5 mmHg−1 × 10−3) versus 301 ± 75 kPa−1 × 10 −3 (40 ± 10 mmHg−1 × 10 −3) for controls, P <0.0005). Linear regression analysis showed a strong correlation between peak negative dP/dt and both diastolic distensibility (r=0.89, P<0.0005) and normalised distensibility (r=0.88, P<0.0125). These data suggest that early diastolic left ventricular relaxation is impaired in congestive cardiomyopathy and that this defect occurs in association with a decrease in left ventricular diastolic compliance.