Sympathetic predominance before tourniquet deflation is associated with a reduction in arterial blood pressure after tourniquet deflation during total knee arthroplasty

High dependency of arterial blood pressure (ABP) on enhanced sympathetic activity, which maintains vascular tone, leads to hypotension after hemodynamic insults that blunt the sympathetic activity. Therefore, we hypothesized that sympathovagal balance before tourniquet deflation (TD) determines the extent of a reduction in ABP after TD during total knee arthroplasty (TKA). Fifty-four hypertensive female patients undergoing TKA under spinal anesthesia were analyzed. The sympathovagal balance [low-to-high frequency ratio of heart rate variability (LF/HF)] before TD was defined as (LF/HF during 5 min before TD-preanesthetic LF/HF)/preanesthetic LF/HF (%). An increase in its value represents a shift in sympathovagal balance toward sympathetic predominance. The percent change in the mean ABP (MAP) after TD was defined as (minimum MAP during 10 min after TD-averaged MAP during 5 min before TD)/averaged MAP during 5 min before TD (%). Simple linear regression was performed to assess the correlation between the sympathovagal balance before TD and change in MAP after TD. The correlation was also assessed by multiple linear regression controlling for age, duration of tourniquet inflation, and spinal anesthesia-induced hypotension. Thirty-two minutes (on average) after tourniquet inflation, the MAP was decreased by 12.1 (-3.0 to 47.9) % [mean (range)] upon TD (P<0.001). The sympathovagal balance before TD was negatively proportional to the change in MAP after TD in both simple and multiple linear regression models (R2=0.323 and 0.340, P<0.001). A shift in sympathovagal balance toward sympathetic predominance before TD is associated with a decrease in ABP after TD.

Factors contributing to cognitive improvement effects of acupuncture in patients with mild cognitive impairment: a pilot randomized controlled trial

Background

Mild cognitive impairment (MCI) is generally regarded as the borderline between cognitive changes of aging and very early Alzheimer’s disease (AD). It is important to develop easily available interventions to delay the progression of MCI to AD. We investigated factors contributing to the cognitive improvement effects of acupuncture to obtain data for developing optimized acupuncture treatments for MCI.

Methods

This outcome assessor-blinded, randomized controlled trial included a full analysis for comparing the efficacy of different acupuncture methods. Thirty-two participants with MCI (i.e., fulfilling the Peterson diagnostic criteria for MCI, K-MMSE scores of 20–23, and MoCA-K scale scores of 0–22) were randomly assigned to basic acupuncture (BA; GV20, EX-HN1, GB20, and GV24 for 30 min), acupoint specificity (AS; adding KI3 to BA), needle duration (ND; BA for 20 min), or electroacupuncture (EA; electrical stimulation to BA) groups (n=8/group) via 1:1:1:1 allocation and administered acupuncture once daily, three times a week for 8 weeks. The measured outcomes included scores on the Korean version of the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-K-cog), Korean version of the Montreal Cognitive Assessment scale (MoCA-K), Center for Epidemiological Studies-Depression Scale, Korean Activities of Daily Living scale, Korean Instrumental Activities of Daily Living scale, and European Quality of Life Five Dimension Five Level Scale. Outcome measurements were recorded at baseline (week 0), intervention endpoint (week 8), and 12 weeks after intervention completion (week 20).

Results

Twenty-five patients with MCI completed the trial (BA group, 8; AS group, 6; ND group, 5; EA group, 6). MoCA-K scores were significantly increased in the BA group compared with the ND (p=0.008, week 8–week 0) and EA groups (p=0.003, week 8–week 0; p=0.043, week 20–week 0). ADAS-K-cog scores were significantly decreased in the BA group compared with the ND group (p=0.019, week 20–week 0).

Conclusions

The BA group showed significant improvement in cognitive function compared to the ND and EA groups. Electrical stimulation and needle duration may contribute to the cognitive improvement effects of acupuncture in patients with MCI.

Trial registration

Clinical Research Information Service; URL:cris.nih.go.kr.; unique identifier: KCT0003430 (registration date: January 16, 2019).

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-021-05296-4.

Effects of Dangguixu-san in patients with acute lateral ankle sprain: a randomized controlled trial

BACKGROUND

Dangguixu-san (DS), a herbal extract, is widely used in Korean medicine to treat pain and swelling caused by ankle sprain. However, there is insufficient evidence regarding the effects of DS on ankle sprains. Accordingly, we assessed the efficacy and safety of DS for the treatment of acute lateral ankle sprain (ALAS).

METHODS

This study was a multicenter (two Korean hospitals), randomized, double-blind, placebo-controlled, parallel-arm clinical trial with a 1:1 allocation ratio that included a per-protocol analysis and sub-analysis based on symptom severity. Forty-eight participants (n = 28 at Semyung University Korean Medicine Hospital in Chungju; n = 20 at DongShin University Gwangju Korean Medicine Hospital) with grade I or II ALAS that occurred within 72 h before enrollment were randomized to a DS (n = 24) or placebo (n = 24) group. Both groups received acupuncture treatment once daily for 5 consecutive days and the trial medication (DS/placebo capsule) three times a day for 7 consecutive days. Primary (visual analog scale [VAS] scores for pain) and secondary (Foot and Ankle Outcome Scores [FAOS], edema, and European Quality of Life Five-Dimension-Five-Level Scale [EQ-5D-5L] scores) outcome measures were recorded at baseline (week 0), the end of the intervention (week 1), and 4 weeks after treatment completion (week 5).

RESULTS

Forty-six participants completed the trial (n = 23 each). Changes in VAS scores, FAOS Symptom/Rigidity, and FAOS Ache from week 1 to week 5 showed significant differences between the two groups. Sub-analyses showed significant differences in changes of FAOS Ache (week 0 to week 5) and VAS scores, total FAOS, and EQ-5D-5L scores (week 1 to week 5) between the two subgroups (grade II). There were no adverse events and significant negative changes in clinical laboratory parameters in both groups.

CONCLUSIONS

Overall, the results of this study are in favor of DS combined with acupuncture and suggest that DS combined with acupuncture is a safe treatment with positive long-term effects in terms of pain reduction and symptom alleviation in patients with grade I or II ALAS.

TRIAL REGISTRATION

Clinical Research Information Service KCT0002374 . Registered on July 11, 2017; retrospectively registered.

Effects of different acupuncture treatment methods on mild cognitive impairment: a study protocol for a randomized controlled trial

Background

Mild cognitive impairment (MCI) is an intermediate state between normal aging and Alzheimer’s disease, which is the world’s most common form of dementia. It is important to identify early and easily available interventions to delay the progression of MCI to Alzheimer’s disease. Acupuncture has been reported to improve the clinical outcomes of MCI treatment. Acupuncture is a complex intervention, involving both specific and non-specific factors associated with therapeutic benefits. Therefore, we intend to obtain basic data for developing an optimal acupuncture treatment for MCI by comparing the effects of different acupuncture treatment methods on cognitive function in MCI patients.

Methods

This study will be a prospective, outcome-assessor-blinded, parallel-arm, single-center (DongShin University Gwangju Korean Medicine Hospital, Republic of Korea), randomized controlled clinical trial. Thirty-two participants with MCI will be randomized in equal numbers to four groups (basic acupuncture (BA), acupoint specificity (AS), needle duration (ND), or electroacupuncture (EA)) and receive acupuncture treatment once per day, 3 days/week for 8 weeks. The BA and ND groups will receive acupuncture treatment for 30 and 20 min, respectively, at Baihui (GV20), Sishencong (EX-HN1), Fengchi (GB20), and Shenting (GV24). The EA group will receive electroacupuncture treatment at the same acupoints for 30 min. The AS group will receive acupuncture treatment at GV20, EX-HN1, GB20, GV24, and Taixi (KI3) for 30 min. The outcome measured will be scores on the Korean version of the Alzheimer’s Disease Assessment Scale—cognitive subscale, the Korean version of the Montreal Cognitive Assessment, the Center for Epidemiological Studies Depression scale, the Korean Activities of Daily Living scale, the Korean Instrumental Activities of Daily Living scale, and the European Quality of Life Five Dimension Five Level scale. All scores will be recorded before intervention, 8 weeks after the first intervention, and 12 weeks after completing the intervention.

Discussion

Four acupuncture protocols will be assessed and compared as potential MCI treatments. This study is expected to provide data to be used in developing an optimal acupuncture method for MCI treatment.

Trial registration

Clinical Research Information Service, KCT0003430. Registered on 16 January 2019.

http://cris.nih.go.kr).

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3670-3) contains supplementary material, which is available to authorized users.

Suppression of creep-regime dynamics in epitaxial ferroelectric BiFeO3 films

Switching dynamics of ferroelectric materials are governed by the response of domain walls to applied electric field. In epitaxial ferroelectric films, thermally-activated ‘creep’ motion plays a significant role in domain wall dynamics, and accordingly, detailed understanding of the system’s switching properties requires that this creep motion be taken into account. Despite this importance, few studies have investigated creep motion in ferroelectric films under ac-driven force. Here, we explore ac hysteretic dynamics in epitaxial BiFeO₃ thin films, through ferroelectric hysteresis measurements, and stroboscopic piezoresponse force microscopy. We reveal that identically-fabricated BiFeO₃ films on SrRuO₃ or La_0.67Sr_0.33MnO₃ bottom electrodes exhibit markedly different switching behaviour, with BiFeO₃/SrRuO₃ presenting essentially creep-free dynamics. This unprecedented result arises from the distinctive spatial inhomogeneities of the internal fields, these being influenced by the bottom electrode’s surface morphology. Our findings further highlight the importance of controlling interface and defect characteristics, to engineer ferroelectric devices with optimised performance.

First Report of Myrothecium roridum Causing Leaf and Stem Rot Disease on Peperomia quadrangularis in Korea

In 2010, symptoms of leaf and stem rot were observed on potted plants (Peperomia quadrangularis) in a greenhouse in Yongin, Korea. The causative pathogen was identified as Myrothecium roridum based on morphological data, internal transcribed spacer sequence analysis, and pathogenicity test. To our knowledge, this is the first report of M. roridum causing leaf and stem rot disease on P. quadrangularis in Korea and elsewhere worldwide.

Morphology and adhesion of mesenchymal stem cells on PLLA, apatite and apatite/collagen surfaces

Biomimetic apatite/collagen composite coating, previously reported particularly with regard to its fabrication, characterization and interaction with osteoblast-like cells, has been investigated in this study to understand the response of human mesenchymal stem cells (hMSC) to such surface. PLLA films and PLLA films with apatite coating were compared with PLLA films with apatite/collagen composite coating. The hMSC morphology in response to such conditions was first observed using fluorescence microscopy. To further understand such cell-material interactions at a molecular level, integrin expression, actin assembly and vinculin-positive focal adhesion plaques were examined. Our results demonstrated that spreading of stem cells on the apatite/collagen composite surface was determined best among the three types of surfaces, followed by the apatite surface and then the PLLA control. Integrin expression on the apatite/collagen surface was higher than those on the apatite surface and PLLA surface. Immunostaining for vinculin and actin suggested that the composite coating on PLLA enhanced the formation of focal adhesion.

Ultrastructure of the Z-organ and Parts of the Female Genital Tract in Xiphinema coxi coxi

Ultrastructure of the Z-organ and associated apophyses in Xiphinema coxi coxi was studied by transmission electron microscopy to determine their structural origin and relationship with other parts of the genital tract. The Z-organ of X. coxi coxi is oval-shaped, ca. 30 microm long and 16 microm wide. It is clearly distinguished from the other parts of the female genital tract by its thick muscular outer wall, epithelium-lined lumen, and 4-5 centrally located apophyses. Each apophysis is continuous with the epithelial lining of the Z-organ, suggesting that it originated from epithelium. The apophyses appear as thickened and densely folded masses forming numerous interlaced pores and (or) chambers containing mucous-like materials and electron-dense crystals. These apophyses are characteristic of a typical Z-organ; no globular structures characteristics of the pseudo-Z-organ were observed. The thickness of the muscular layer of the oviduct and uterus varied with position. The overall Z-organ ultrastructure of this study, including body wall and internal apophyses, was comparable to the typical Z-organ of X. ifacolum. This suggests that X. coxi coxi should be classified as a Xiphinema species that contains the typical Z-organ.

Integrin-dependent human macrophage migration induced by oscillatory electrical stimulation

Electrical stimulation has been used to promote wound healing. The mechanisms by which such stimulation could interact with biological systems to accelerate healing have not been elucidated. One potential mechanism could involve stimulation of macrophage migration to the site of a wound. Here we report that oscillatory electric fields induce human macrophage migration. Macrophages exposed to a 1 Hz, 2 V/cm field show an induced migration velocity of 5.2+/-0.4 x 10(-2) microm/min and a random motility coefficient of 4.8+/-1.4 x 10(-2) microm2/min on a glass substrate. Electric field exposure induces reorganization of microfilaments from ring-like structures at the cell periphery to podosomes that are confined to the contact sites between cell and substrate, suggesting that the cells are crawling on glass. Treatment of cells with monoclonal antibodies directed against beta2-integrins prior to field exposure prevents cell migration, indicating that integrin-dependent signaling pathways are involved. Electric fields cause macrophage migration on laminin or fibronectin coated substrates without inducing podosome formation or changes in cellular morphology. The migration velocity is not significantly altered but the random movement is suppressed, suggesting that cell movements on a laminin- or fibronectin-coated surface are not mediated by cell crawling. It is suggested that electric field-induced macrophage migration utilizes several modes of cell movement, including cell crawling and possibly cell rolling.

Mild spherocytosis and altered red cell ion transport in protein 4. 2-null mice

Protein 4.2 is a major component of the red blood cell (RBC) membrane skeleton. We used targeted mutagenesis in embryonic stem (ES) cells to elucidate protein 4.2 functions in vivo. Protein 4. 2-null (4.2(-/-)) mice have mild hereditary spherocytosis (HS). Scanning electron microscopy and ektacytometry confirm loss of membrane surface in 4.2(-/-) RBCs. The membrane skeleton architecture is intact, and the spectrin and ankyrin content of 4. 2(-/-) RBCs are normal. Band 3 and band 3-mediated anion transport are decreased. Protein 4.2(-/-) RBCs show altered cation content (increased K+/decreased Na+)resulting in dehydration. The passive Na+ permeability and the activities of the Na-K-2Cl and K-Cl cotransporters, the Na/H exchanger, and the Gardos channel in 4. 2(-/-) RBCs are significantly increased. Protein 4.2(-/-) RBCs demonstrate an abnormal regulation of cation transport by cell volume. Cell shrinkage induces a greater activation of Na/H exchange and Na-K-2Cl cotransport in 4.2(-/-) RBCs compared with controls. The increased passive Na+ permeability of 4.2(-/-) RBCs is also dependent on cell shrinkage. We conclude that protein 4.2 is important in the maintenance of normal surface area in RBCs and for normal RBC cation transport.

Transmembrane calcium influx induced by ac electric fields

Exogenous electric fields induce cellular responses including redistribution of integral membrane proteins, reorganization of microfilament structures, and changes in intracellular calcium ion concentration ([Ca2+]i). Although increases in [Ca2+]i caused by application of direct current electric fields have been documented, quantitative measurements of the effects of alternating current (ac) electric fields on [Ca2+]i are lacking and the Ca2+ pathways that mediate such effects remain to be identified. Using epifluorescence microscopy, we have examined in a model cell type the [Ca2+]i response to ac electric fields. Application of a 1 or 10 Hz electric field to human hepatoma (Hep3B) cells induces a fourfold increase in [Ca2+]i (from 50 nM to 200 nM) within 30 min of continuous field exposure. Depletion of Ca2+ in the extracellular medium prevents the electric field-induced increase in [Ca2+]i, suggesting that Ca2+ influx across the plasma membrane is responsible for the [Ca2+]i increase. Incubation of cells with the phospholipase C inhibitor U73122 does not inhibit ac electric field-induced increases in [Ca2+]i, suggesting that receptor-regulated release of intracellular Ca2+ is not important for this effect. Treatment of cells with either the stretch-activated cation channel inhibitor GdCl3 or the nonspecific calcium channel blocker CoCl2 partially inhibits the [Ca2+]i increase induced by ac electric fields, and concomitant treatment with both GdCl3 and CoCl2 completely inhibits the field-induced [Ca2+]i increase. Since neither Gd3+ nor Co2+ is efficiently transported across the plasma membrane, these data suggest that the increase in [Ca2+]i induced by ac electric fields depends entirely on Ca2+ influx from the extracellular medium.

Estradiol induces the calcium-dependent translocation of endothelial nitric oxide synthase

Although estrogen is known to stimulate nitric oxide synthesis in vascular endothelium, the molecular mechanisms responsible for this effect remain to be elucidated. Using quantitative immunofluorescence imaging approaches, we have investigated the effect of estradiol on the subcellular targeting of endothelial nitric oxide synthase (eNOS) in bovine aortic endothelial cells. In unstimulated endothelial cells, eNOS is predominantly localized at the cell membrane. Within 5 min after the addition of estradiol, most of the eNOS translocates from the membrane to intracellular sites close to the nucleus. On more prolonged exposure to estradiol, most of the eNOS returns to the membrane. This effect of estradiol is evident at a concentration of 1 pM, and a maximal estradiol effect is seen at a concentration of 1 nM. Neither progesterone nor testosterone has any effect on eNOS distribution. After estradiol addition, a transient rise in intracellular Ca2+ concentration precedes eNOS translocation. Both the Ca2+-mobilizing and eNOS-translocating effects of estradiol are completely blocked by the estrogen receptor antagonist ICI 182,780, and the intracellular Ca2+ chelator 1,2-bis-(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA) prevents estradiol-induced eNOS translocation. Use of the nitric oxide-specific dye diaminofluorescein shows that estradiol treatment increases nitric oxide generation by endothelial cells; this response is blocked by ICI 182,780 and by the eNOS inhibitor Nomega-nitro-L-arginine. These results show that estradiol induces subcellular translocation of eNOS by a rapid, Ca2+-dependent, receptor-mediated mechanism, and they suggest a nongenomic role for estrogen in the modulation of NO-dependent vascular tone.

Membrane dynamics of the water transport protein aquaporin-1 in intact human red cells

Aquaporin-1 (AQP1) is the prototype integral membrane protein water channel. Although the three-dimensional structure and water transport function of the molecule have been described, the physical interactions between AQP1 and other membrane components have not been characterized. Using fluorescein isothiocyanate-anti-Co3 (FITC-anti-Co3), a reagent specific for an extracellular epitope on AQP1, the fluorescence photobleaching recovery (FPR) and fluorescence imaged microdeformation (FIMD) techniques were performed on intact human red cells. By FPR, the fractional mobility of fluorescently labeled AQP1 (F-alphaAQP1) in the undeformed red cell membrane is 66 +/- 10% and the average lateral diffusion coefficient is (3.1 +/- 0.5) x 10(-11) cm2/s. F-alphaAQP1 fractional mobility is not significantly affected by antibody-induced immobilization of the major integral proteins band 3 or glycophorin A, indicating that AQP1 does not exist as a complex with these proteins. FIMD uses pipette aspiration of individual red cells to create a constant but reversible skeletal density gradient. F-alphaAQP1 distribution, like that of lipid-anchored proteins, is not at equilibrium after microdeformation. Over time, approximately 50% of the aspirated F-alphaAQP1 molecules migrate toward the membrane portion that had been maximally dilated, the aspirated cap. Based on the kinetics of migration, the F-alphaAQP1 lateral diffusion coefficient in the membrane projection is estimated to be 6 x 10(-10) cm2/s. These results suggest that AQP1 lateral mobility is regulated in the unperturbed membrane by passive steric hindrance imposed by the spectrin-based membrane skeleton and/or by skeleton-linked membrane components, and that release of these constraints by dilatation of the skeleton allows AQP1 to diffuse much more rapidly in the plane of the membrane.

Regulation of band 3 rotational mobility by ankyrin in intact human red cells

Ankyrin mutations and combined spectrin and ankyrin deficiency are prominent features of red blood cells (RBCs) in patients with hereditary spherocytosis (HS). Band 3 is the most abundant integral protein in the human RBC membrane. Previous studies have shown that the lateral mobility, but not the rotational mobility, of band 3 is increased in RBCs from patients with severe autosomal recessive HS and selective spectrin deficiency. These observations are consistent with the steric hindrance model of lateral mobility restriction. Here we use the fluorescence photobleaching recovery and polarized fluorescence depletion techniques to measure the lateral and rotational mobility of band 3 in intact RBCs from six patients with HS, ankyrin mutations, and combined spectrin and ankyrin deficiency. As predicted by the steric hindrance model, the lateral diffusion rate of band 3 is greater in spectrin- and ankyrin-deficient RBCs than in control cells, and the magnitude of the increase correlates with the degree of spectrin deficiency. Unlike RBCs from patients with HS and selective spectrin deficiency, however, HS RBCs with ankyrin mutations exhibit a marked increase in band 3 rotational diffusion. The magnitude of the increase correlates inversely with the ankyrin/band 3 ratio and with the fraction of band 3 retained in the membrane skeleton following detergent extraction. These data suggest that ankyrin deficiency relaxes rotational constraints on the major (slowly rotating) population of band 3 molecules. Increases in band 3 rotation could be due to release of band 3 from low-affinity binding sites on ankyrin.

Receptor-regulated translocation of endothelial nitric-oxide synthase

The endothelial nitric-oxide synthase (eNOS) is activated by transient increases in intracellular Ca2+ elicited by stimulation of diverse receptors, including bradykinin B2 receptors on endothelial cells. eNOS and B2 receptors are targeted to specialized signal-transducing domains in the plasma membrane termed plasmalemmal caveolae. Targeting to caveolae facilitates eNOS activation following receptor stimulation, but in resting cells, eNOS is tonically inhibited by its interactions with caveolin, the scaffolding protein in caveolae. We used a quantitative approach exploiting immunofluorescence microscopy to investigate regulation of the subcellular distribution of eNOS in endothelial cells by bradykinin and Ca2+. In resting cells, most of the eNOS is localized at the cell membrane. However, within 5 min following addition of bradykinin, nearly all the eNOS translocates to structures in the cell cytosol; following more protracted incubations with bradykinin, most of the cytosolic enzyme subsequently translocates back to the cell membrane. The bradykinin-induced internalization of eNOS is completely abrogated by the intracellular Ca2+ chelator BAPTA; conversely, Ca2+-mobilizing drugs and agonists promote eNOS translocation. These results establish that eNOS targeting to the membrane is labile and is subject to receptor-regulated Ca2+-dependent reversible translocation, providing another point for regulation of NO-dependent signaling in the vascular endothelium.

Temporal synthesis of band 3 oligomers during terminal maturation of mouse erythroblasts. Dimers and tetramers exist in the membrane as preformed stable species

Band 3, the anion transport protein of the erythrocyte membrane, exists in the membrane as a mixture of dimers (B3D) and tetramers (B3T). The dimers are not linked to the skeleton and constitute the free mobile band 3 fraction. The tetramers are linked to the skeleton by their interaction with ankyrin. In this report we have examined the temporal synthesis and assembly of band 3 oligomers into the plasma membrane during red cell maturation. The oligomeric state of newly synthesized band 3 in early and late erythroblasts was analyzed by size-exclusion high-pressure liquid chromatography of band 3 extracts derived by mild extraction of plasma membranes with the nonionic detergent C12E8 (octaethylene glycol n-dodecyl monoether). This analysis revealed that at the early erythroblast stage, the newly synthesized band 3 is present predominantly as tetramers, whereas at the late stages of erythroid maturation, it is present exclusively as dimers. To examine whether the dimers and tetramers exist in the membrane as preformed stable species or whether they are interconvertible, the fate of band 3 species synthesized during erythroblast maturation was examined by pulse-chase analysis. We showed that the newly synthesized band 3 dimers and tetramers are stable and that there is no interconversion between these species in erythroblast membranes. Pulse-chase analysis followed by cellular fractionation showed that, in early erythroblasts, the newly synthesized band 3 tetramers are initially present in the microsomal fraction and later incorporated stably into the plasma membrane fraction. In contrast, in late erythroblasts the newly synthesized band 3 dimers move rapidly to the plasma membrane fraction but then recycle between the plasma membrane and microsomal fractions. Fluorescence photobleaching recovery studies showed that significant fractions of B3T and B3D are laterally mobile in early and late erythroblast plasma membranes, respectively, suggesting that many B3T-ankyrin complexes are unattached to the membrane skeleton in early erythroblasts and that the membrane skeleton has yet to become tightly organized in late erythroblasts. We postulate that in early erythroblasts, band 3 tetramers are transported through microsomes and stably incorporated into the plasma membrane. However, when ankyrin synthesis is downregulated in late erythroblasts, it appears that B3D are rapidly transported to the plasma membrane but then recycled between the plasma membrane and microsomal compartments. These observations may suggest novel roles for membrane skeletal proteins in stabilizing integral membrane protein oligomers at the plasma membrane and in regulating the endocytosis of such proteins.

Red cell membranes of ankyrin-deficient nb/nb mice lack band 3 tetramers but contain normal membrane skeletons

The role of ankyrin in the formation and stabilization of the spectrin-based skeletal meshwork and of band 3 oligomers was studied by characterizing, in nb/nb mouse red cells, the effect of ankyrin deficiency on skeletal ultrastructure, band 3-skeleton associations, and band 3 oligomeric states. Despite severe ankyrin deficiency, nb/nb mouse red cell skeletal components formed a relatively uniform two-dimensional hexagonal array of junctional complexes cross-linked by spectrin tetramers. Treatment of nb/nb ghosts with the nonionic detergent C12E8 (octaethylene glycol n-dodecyl monoether) resulted in nearly complete extraction of band 3. The extracted band 3 was present exclusively as band 3 dimers. Fluorescence photobleaching recovery and polarized fluorescence depletion measurements showed increases in the laterally (33% vs 10%) and rotationally (90% vs 76%) mobile fractions of band 3 in intact nb/nb compared to control red cells. The rotational correlation time of the major fraction of band 3 molecules was 10-fold shorter in nb/nb compared to control red cells, indicating a significant relaxation of rotational constraints in nb/nb cells. These data suggest that, although ankyrin plays a major role in strengthening the attachment of the skeleton to the membrane bilayer, ankyrin is not required for the formation of a stable two-dimensional spectrin-based skeleton. The absence of band 3 tetramers in the membrane of ankyrin-deficient red cells suggests that ankyrin is required for the formation of stable band 3 tetramers.

A multiparameter analysis of sickle erythrocytes in patients undergoing hydroxyurea therapy

During 24 weeks of hydroxyurea treatment, we monitored red blood cell (RBC) parameters in three patients with sickle cell disease, including F-cell and F-reticulocyte profiles, distributions of delay times for intracellular polymerization, sickle erythrocyte adherence to human umbilical vein endothelial cells in a laminar flow chamber, RBC phthalate density profiles, mean corpuscular hemoglobin concentration and cation content, reticulocyte mean corpuscular hemoglobin concentration, 1H-nuclear magnetic resonance transverse relaxation rates of packed RBCs, and plasma membrane lateral and rotational mobilities of band 3 and glycophorins. Hydroxyurea increases the fraction of cells with sufficiently long delay times to escape the microcirculation before polymerization begins. Furthermore, high pretreatment adherence to human umbilical vein endothelial cells of sickle RBCs decreased to normal after only 2 weeks of hydroxyurea treatment, preceding the increase in fetal hemoglobin levels. The lower adhesion of sickle RBCs to endothelium would facilitate escape from the microcirculation before polymerization begins. Hydroxyurea shifted several biochemical and biophysical parameters of sickle erythrocytes toward values observed with hemoglobin SC disease, suggesting that hydroxyurea moderates sickle cell disease toward the milder, but still clinically significant, hemoglobin SC disease. The 50% reduction in sickle crises documented in the Multicenter Study of Hydroxyurea in Sickle Cell Disease is consistent with this degree of erythrocyte improvement.

Screening of Carnation Cultivars for Resistance to Meloidogyne incognita

A total of 33 carnation cultivars cultured in Korea were screened for resistance to the southern root-knot nematode, Meloidogyne incognita. Carnations were tested by either inoculating with 5,000 eggs or by transplanting into a mixture of bedding medium and soil infested with an average of 435 second-stage juveniles/300 cm(3) soil. Cultivars, Desio, Castelaro, Kappa, Rara, Izu Pink, Target, and Antalia were highly resistant to M. incognita. Twelve cultivars were moderately resistant, and the remaining 14 cultivars were susceptible. These results were similar to those obtained when the cultivars were subjected to field populations of the condition on a carnation farm.

Reorganization of microfilament structure induced by ac electric fields

AC electric fields induce redistribution of integral membrane proteins. Cell-surface receptor redistribution does not consistently follow electric field lines and depends critically on the frequency of the applied ac electric fields, suggesting that mechanisms other than electroosmosis are involved. We hypothesized that cytoskeletal reorganization is responsible for electric field-induced cell-surface receptor redistribution, and used fluorescence video microscopy to study the reorganization of microfilaments in human hepatoma (Hep3B) cells exposed to low-frequency electric fields ranging in strength from 25 mV/cm to 20 V/cm (peak to peak). The frequency of the applied electric field was varied from 1 to 120 Hz and the field exposure duration from 1 to 60 min. In control cells, cytoplasmic microfilaments were aligned in the form of continuous parallel cables along the longitudinal axis of the cell. Exposure of cells to ac electric fields induced alterations in microfilament structure in a manner that depended on the frequency of the applied field. A 1 or 10 Hz ac field caused microfilament reorganization from continuous, aligned cable structures to discontinuous globular patches. In contrast, the structure of microfilaments in cells exposed to 20-120 Hz electric fields did not differ from that in control cells. The extent of microfilament reorganization increased nonlinearly with the electric field strength. The characteristic time for microfilament reorganization in cells exposed to a 1 Hz, 20 V/cm electric field was approximately 5 min. Applied ac electric fields could initiate signal transduction cascades, which in turn cause reorganization of cytoskeletal structures.

Molecular basis of altered red blood cell membrane properties in Southeast Asian ovalocytosis: role of the mutant band 3 protein in band 3 oligomerization and retention by the membrane skeleton

Southeast Asian ovalocytosis (SAO) is an asymptomatic trait characterized by rigid, poorly deformable red cells that resist invasion by several strains of malaria parasites. The underlying molecular genetic defect involves simple heterozygous state for a mutant band 3 protein, which contains a deletion of amino acids 400 through 408, linked with a Lys 56-to-Glu substitution (band 3-Memphis polymorphism). To elucidate the contribution of the mutant SAO band 3 protein to increased SAO red blood cell (RBC) rigidity, we examined the participation of the mutant SAO band 3 protein in increased band 3 attachment to the skeleton and band 3 oligomerization. We found first that SAO RBC skeletons retained more band 3 than normal cells and that this increased retention preferentially involved the mutant SAO band 3 protein. Second, SAO RBCs contained a higher percentage of band 3 oligomer-ankyrin complexes than normal cells, and these oligomers were preferentially enriched by the mutant SAO protein. At the ultrastructural level, the increased oligomer formation of SAO RBCs was reflected by stacking of band 3-containing intramembrane particles (IMP) into longitudinal strands. The IMP stacking was not reversed by treating SAO RBCs in alkaline pH (pH 11), which is known to weaken ankyrin-band 3 interactions, or by removing the cytoplasmic domain of band 3 from SAO membranes with trypsin. Finally, we found that band 3 protein in intact SAO RBCs exhibited a markedly decreased rotational mobility, presumably reflecting the increased oligomerization and the membrane skeletal association of the SAO band 3 protein. We propose that the mutant SAO band 3 has an increased propensity to form oligomers, which appear as longitudinal strands of IMP and exhibit increased association with membrane skeleton. This band 3 oligomerization underlies the increase in membrane rigidity by precluding membrane skeletal extension, which is necessary for membrane deformation.

Induced redistribution of cell surface receptors by alternating current electric fields

The molecular mechanisms that underlie the biological effects of low frequency sinusoidal electric fields may involve induced changes in the physical state of charged cell surface receptors. We have used intensified fluorescence video microscopy to study the redistribution of cell surface receptors, including transferrin receptors (TFR) and low density lipoprotein receptors (LDL-R), in response to externally applied alternating current electric fields in the 3 to 23 V/cm range (peak to peak). Redistribution of both TFR and LDL-R was prominent at frequencies of 1 and 10 Hz but negligible at frequencies of 60 and 120 Hz. Application of a 1 Hz, 23 V/cm field for 15 min caused a twofold change in local TFR surface density, whereas application of a 60 Hz, 23 V/cm field resulted in no significant TFR redistribution. The extent of TFR redistribution induced by a 1 Hz field changed by only 20% over the field strength range from 3.5 to 23 V/cm. AC field-induced cell surface receptor migration did not consistently follow electric field lines, suggesting that mechanisms more complex than classical electrophoresis and electroosmosis mediate receptor redistribution. Joule heating and plasma membrane calcium channel activation were shown not to be involved in the mechanism of receptor redistribution. Applied external electric fields may reorganize cytoskeletal and plasma membrane structures, providing pathways for cell surface receptors to migrate anharmonically.

Deoxygenation affects fluorescence photobleaching recovery measurements of red cell membrane protein lateral mobility

We have used the fluorescence photobleaching recovery technique to study the dependence on oxygen tension of the lateral mobility of fluorescently labeled band 3, the phospholipid analogue fluorescein phosphatidylethanolamine, and glycophorins in normal red blood cell membranes. Band 3 protein and sialic acid moieties on glycophorins were labeled specifically with eosin maleimide and fluorescein thiosemicarbazide, respectively. The band 3 diffusion rate increased from 1.7 x 10(-11) cm2 s-1 to 6.0 x 10(-11) cm2 s-1 as oxygen tension was decreased from 156 to 2 torr, and a further increase to 17 x 10(-11) cm2 s-1 occurred as oxygen tension was decreased from 2 to 0 torr. The fractional mobility of band 3 decreased from 58 to 32% as oxygen tension was decreased from 156 to 0 torr. The phospholipid diffusion coefficient remained constant as oxygen tension was decreased from 156 to 20 torr, but increased from 2.3 x 10(-9) cm2 s-1 to 7.1 x 10(-9) cm2 s-1 as oxygen tension was decreased from 20 to 0 torr. Neither the diffusion coefficient nor the fractional mobility of glycophorins changed significantly at low oxygen tension. Under non-bleaching excitation conditions, intensities of fluorescence emission were identical for oxygenated and deoxygenated eosin-labeled RBCs. Deoxygenated eosin-labeled RBCs required 160-fold greater laser intensities than did oxygenated RBCs to achieve comparable extents of photobleaching, however. Oxygen seems to act as a facilitator of fluorophore photobleaching and may thereby protect the fluorescently labeled red cell membrane from photodamage. Removal of oxygen may allow excited state fluorophores in close proximity to the plasma membrane to react with neighboring proteins or lipids during photobleaching. This effect has important implications for the ability of the fluorescence photobleaching recovery technique to report accurate lateral mobilities of cell membrane molecules under hypoxic conditions.

Duplication of 10 nucleotides in the erythroid band 3 (AE1) gene in a kindred with hereditary spherocytosis and band 3 protein deficiency (band 3PRAGUE)

We describe a duplication of 10 nucleotides (2,455-2,464) in the band 3 gene in a kindred with autosomal dominant hereditary spherocytosis and a partial deficiency of the band 3 protein that is reflected by decreased rate of transmembrane sulfate flux and decreased density of intramembrane particles. The mutant allele potentially encodes an abnormal band 3 protein with a 3.5-kD COOH-terminal truncation; however, we did not detect the mutant protein in the membrane of mature red blood cells. Since the mRNA levels for the mutant and normal alleles are similar and since the band 3 content is the same in the light and dense red cell fractions, we conclude that the mutant band 3 is either not inserted into the plasma membrane or lost from the membrane prior to the release of red blood cells into circulation. We further show that the decrease in band 3 content principally involves the dimeric laterally and rotationally mobile fraction of the band 3 protein, while the laterally immobile and rotationally restricted band 3 fraction is left essentially intact. We propose that the decreased density of intramembrane particles decreases the stability of the membrane lipid bilayer and causes release of lipid microvesicles that leads to surface area deficiency and spherocytosis.

Monomer diffusion and polymer alignment in domains of sickle hemoglobin

We have used polarized absorbance to observe the process of monomer accretion and polymer alignment which occurs in domains of sickle hemoglobin that are formed and maintained by laser photolysis. These diffusion and alignment processes have been studied as a function of initial concentration and temperature (initial and final), as well as beam size and domain number. Monomers are found to diffuse into growing polymer domains with a rate that is essentially temperature and concentration independent, but which depends on the size of the final domain boundaries, and the number of domains within a boundary. The final concentrations achieved are very close to those found in packed centrifugation experiments (50-55 g/dl) and are approximately independent of starting temperature and concentration. The influx of monomers is accompanied by polymer alignment, and the amount aligned is proportional to the amount diffused throughout the process. We propose that polymer alignment controls the influx of added monomers into the growing domain.

Morphological Variation among 23 Xiphinema americanum Populations

Morphometrics of 23 United States populations of Xiphinema americanum sensu lato, sharing the characteristics of an offset lip region and conoid tail, were examined and analyzed statistically by canonical discriminant analysis (CDA). Specimens were collected from Arkansas, Georgia, Tennessee, Mississippi, Florida, Oklahoma, California, and North Dakota. Eleven measurements and body ratios obtained from female specimens were used in the analysis. Xiphinema americanum, X. bricolensis, X. californicum, X. citricolum, X, intermedium, X. tarjanense, and X. thornei, and one undescribed species were identified among the 23 populations. Three groups -- X. americanum-group, X. californicum-group, and X. intermedium-group (X. intermedium and X. tarjanense) -- were formed and four populations belonging to four different species were separated consistently from these groups in CDA scatterplots of the 23 populations. Composition of the groups was somewhat related to the geographical origins of the populations in the groups. A population from California had morphometrics intermediate between X. americanum and X. californicum. Separation between the X. americanum-group and X. californicum-group in the CDA scatterplots was not as distinct as that between them and the X. intermedium-group or between any of the three groups and the four single outlying populations.

Monomer diffusion into polymer domains in sickle hemoglobin

The gelation of sickle hemoglobin includes the formation of spherulitic arrays of polymers, known as polymer domains, which are an intrinsic result of the polymer formation mechanism. We have observed the diffusion of monomers into domains as they form, which substantially increases the total concentration of hemoglobin within the domain. The maximum total concentration attained is comparable with the pellet concentration of 0.5-0.55 g/cm3 obtained in sedimentation experiments. The half time for this process is approximately 50 s for domains of 25 microns radius, and is approximately independent of temperature. The shape of the diffusion progress curves as well as the deduced diffusion constants, and their weak temperature dependence are consistent with a simple model of hemoglobin monomer diffusion into the domain.

Scanning electron microscopy of xiphinema, longidorus, and californidorus stylet morphology

Stylet ultrastructure of five Xiphinema, four Longidorus, and three Californidorus species was compared by scanning electron microscopy. Morphological differences were seen in the odontophores and odontostyle bases between the genera and some of the species. All Xiphinema studied had well-developed odontophore flanges; the Longidorus species lacked flanges, except for weakly developed ones in L. diadecturus; and none of the Californidorus had flanges. Three sinuses were present in the odontophores of all species. The sinuses varied in length depending upon species. In Xiphinema and Californidorus the odontostyle bases had distinct overlapping collars, but in Longidorus the collars were absent except for L. diadecturus. The odontostyle-odontophore junction from a lateral view appeared as a slanted transverse line in all the species, but in a dorsal view of Xiphinema and Californidorus it was V-shaped. Dorsal longitudinal seams of the odontostyle and odontophore were observed in all the species. The dorsally located odontostyle aperture was ca. 1 mum from the anterior end in all species, except in one Longidorus sp. it was ca. 4 mum from the end.

Observations of All Postembryonic Stages of Xiphinema coxi coxi (Nematoda: Longidoridae)

Initial morphometric data and descriptions of males and the four juvenile stages of Xiphinema coxi coxi Tarjan, 1964 collected from soil about the roots of alfalfa (Medicago sativa L.) at Gainesville, Florida, and from a greenhouse microplot at Fayetteville, Arkansas, are given. Males were similar morphometrically and in shape to females and had 3-5 preanal supplements. The four juvenile stages were easily separated by differences in body size, odontostyle, and replacement odontostyle lengths. Supplemental morphometric data for females are given along with scanning electron microscope ultrastructural information. Three X. coxi coxi females with abnormal gonad development are reported.