Lifetime-Extending 3-(4-Phenylbenzo[4,5]thieno[3,2-d]pyrimidin-2-yl)benzonitrile Acceptor for Thermally Activated Delayed Fluorescence Emitters

Highly efficient and long-living green thermally activated delayed fluorescence (TADF) organic light-emitting diodes (OLEDs) were developed using benzothienopyrimidine-4-benzonitrile acceptor-derived compounds as the TADF emitters. A molecular design merging the benzothienopyrimidine-4-benzonitrile acceptor with either indolocarbazole or diindolocarbazole was employed to prepare two TADF emitters, 5-(2-phenylbenzo[4,5]thieno[3,2-d]pyrimidin-4-yl)-2-(5-phenylindolo[3,2-a]carbazol-12(5H)-yl)benzonitrile and 2-(10,15-diphenyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazol-5-yl)-5-(2-phenylbenzo[4,5]thieno[3,2-d]pyrimidin-4-yl)benzonitrile (BTPDIDCz), as the green and greenish-yellow emitters. Among the two emitters, BTPDIDCz with the diindolocarbazole donor combined with the benzothienopyrimidine-4-benzonitrile acceptor demonstrated a high external quantum efficiency of 24.5% and 3 times longer device lifetime than the state-of-the-art green emitter. This work proposed the potential of benzothienopyrimidine-4-benzonitrile as the acceptor for long lifetime in TADF emitters.

Rational Molecular Design Overcoming the Long Delayed Fluorescence Lifetime and Serious Efficiency Roll-Off in Blue Thermally Activated Delayed Fluorescent Devices

Blue thermally activated delayed fluorescent (TADF) devices with short excited-state lifetime, high reverse intersystem crossing rate, and low-efficiency roll-off were developed by managing the molecular structure of donor-acceptor-type blue emitters. Three isomers of blue TADF emitters with a diphenyltriazine acceptor and three carbazole donors were synthesized. The position of the donor moieties in the phenyl linker connecting the donor and acceptor moieties was controlled to devise compounds with a short delayed fluorescence lifetime. A blue TADF emitter with three carbazole donors at 2-, 3-, and 4- positions of a phenyl linker shortened the excited state lifetime to 4.1 μs, showed a high external quantum efficiency of 20.4 %, and low efficiency roll-off of less than 10 % at 1000 cd m^-2 . Therefore, a molecular design distorting the donors by aligning them in a consecutive way is useful to resolve the issues of long delayed fluorescence lifetime and efficiency roll-off of blue TADF devices.

Dihedral Angle Control of Blue Thermally Activated Delayed Fluorescent Emitters through Donor Substitution Position for Efficient Reverse Intersystem Crossing

This study shows a molecular design strategy for controlling the dihedral angle of two carbazole donors linked to a 2,4-diphenyl-1,3,5-triazine acceptor by a phenyl unit. Using this approach, six thermally activated delayed fluorescence emitters were synthesized with donors placed in various positions around a central phenyl core, and the photophysical relationship between the donor position and its dihedral angle was investigated. We demonstrate that this angle can affect both the strength of the charge transfer state and the conjugation across the entire molecule, effectively changing the singlet-triplet energy gap of the system. We conclude that materials containing two substituted -ortho donors or one -ortho and an adjacent -meta have the smallest energy gaps and the shortest delayed fluorescence lifetimes. On the other hand, emitters with no -ortho substituted donors have larger energy gaps and slow-to-negligible delayed fluorescence. When applying these materials to organic light-emitting diodes, these blue-emitting devices have a range of electrical properties, the best producing efficiencies as high as 21.8% together with high resistance to roll-off that correlate with the reverse intersystem crossing rates obtained.

A Case of Ectopic Paragonimiasis in a 17th Century Korean Mummy

Archaeoparasitological studies on fossilized feces obtained from Joseon Dynasty (1392-1910 CE) mummies have provided invaluable data on the patterns of parasitic infection in pre-modern Korean societies. In our recent radiological investigation of a 17th century Joseon mummy discovered in Cheongdo (South Korea), we located a liver mass just below the diaphragm. Anatomical dissection confirmed the presence of a mass of unknown etiology. A subsequent parasitological examination of a sample of the mass revealed a large number of ancient Paragonimus sp. eggs, making the current report the first archaeoparasitological case of liver abscess caused by ectopic paragonimiasis.

Effects of resistance training on central blood pressure in obese young men

Central blood pressure is a predictor of the risk of cardiovascular disease (CVD), and the effects of resistance training (RT) on central blood pressure are largely unknown. This study explored the effects of high-intensity RT on central blood pressure, indices of arterial stiffness and wave reflection and inflammatory/atherogenic markers in overweight or obese, sedentary young men. Thirty-six participants were randomized to RT (12 weeks of training, 3/wk, n=28) or control groups (C, 12 weeks of no training, n=8) and assessed for changes in central and brachial blood pressures, augmentation index (AIx), carotid-femoral pulse wave velocity (cfPWV), carotid intima-media thickness (cIMT), body composition, lipids and inflammatory/atherogenic markers. High-intensity RT resulted in decreased central and brachial systolic/diastolic blood pressures (all P0.03), despite not altering AIx (P=0.34) or cfPWV (P=0.43). The vascular endothelial growth factor increased (P=0.03) after RT, without any change in cIMT, C-reactive protein, oxidized LDL (oxLDL) or other inflammatory markers (all P0.1). Changes in the central systolic blood pressure (cSBP) were positively correlated with changes in oxLDL (r=0.42, P=0.03) and soluble E-selectin (r=0.41, P=0.04). In overweight/obese young men, high-intensity RT decreases cSBP, independently of weight loss and changes in arterial stiffness. The cardioprotective effects of RT may be related to effects on central blood pressure.

Finding ancient parasite larvae in a sample from a male living in late 17th century Korea

Parasitological examination of samples from tombs of the Korean Joseon Dynasty (1392-1910) could be helpful to researchers in understanding parasitic infection prevalence in pre-industrial Korean society. Whereas most of our previous parasitological studies revealed the presence of ancient parasite eggs in coprolites of Korean mummies, a sample from a man living in late 17th century Korea proved to be relatively unique in possessing what appeared to be several species of parasite larvae. The larvae identified included Strongyloides stercoralis and Trichostrongylus spp., along with eggs of Ascaris lumbricoides, Trichuris trichiura, and Paragonimus westermani. Since ancient parasite larvae retain enough morphology to make proper species identification possible, even after long burial times, the examination of parasite larvae within ancient samples will be conducted more carefully in our future work.

Anatomic variations of the infraorbital fat compartment

Resection of the infraorbital fat is performed in blepharoplasty of the lower eyelid, however, the previous anatomical reports on its compartmentalization have been in disagreement. The aim of this study was to classify the infraorbital fat based on the extent of compartmentalization, and to clarify its topographic relationship with the surrounding structures. Sixty orbits from 30 cadavers were dissected. The infraorbital fat was classified into four types based on its compartmentalization. In type I, which was the most common type (60.0%), the infraorbital fat was compartmentalised into three encapsulated medial, central, and lateral parts, which were side by side. In type II (11.7%), the medial or lateral compartment, or both compartments were under the central fat compartment. In type III (26.7%), there were two compartments, the medial and remaining part or the lateral and remaining part. In type IV (1.7%), the fat was not compartmentalised, but presented as a single pad. The average heights from the inferior orbital rim, the average widths, and the average distances from the fornix were 7.3, 17.2, and 7.1 mm in the medial compartment, 8.9, 24.2, and 8.0mm in the central compartment, and 8.1, 17.2, and 6.9 mm in the lateral compartment, respectively. The average distance from the end of the margin of the stretched lower eyelid to the most cephalic point in the compartments was 8.6 mm. These results are relevant to blepharoplasty with removal of the infraorbital fat.

The presence of megamitochondria in the ellipsoid of photoreceptor inner segment of the zebrafish retina

Although the megamitochondria (MM) were localized in various pathological conditions, normal retina of some mammalian species was reported to include MM for various physiological roles. However, it was not clearly confirmed whether the MM is present in the retina of lower vertebrate as well. In this study, we tried to show the presence of the MM in the zebrafish retina using electron microscopic technique. In all the photoreceptors including rods, cones and double cones of the zebrafish retina, MM were observed in the ellipsoid of inner segment. In the photoreceptor epllipsoid of the zebrafish retina, the mitochondria located in the central portion of the ellipsoid had a highly electron-dense matrix, which were accompanied by the mitochondria with electron-lucent matrix in the apical portion of the ellipsoid. The presence of MM was more clearly discernable in the rods, which were localized under the double cones. This finding is somewhat different from those observed in the previous studies because MM were localized in the inner segment of cones, but were not in those of rods in the case of mammalian retina. Although the exact physiological meaning for the presence of MM in some vertebrate species should be further studied, the present study could show that the MM in the ellipsoid of the retinal photoreceptors was not only restricted in some mammalian species.

Branching patterns and symmetry of the course of the facial artery in Koreans

The topography and the course of the facial artery were investigated in 47 Korean cadavers. The final branch of the facial artery was the lateral nasal branch in 44.0% whereas it was the angular branch in 36.3% of the cases. In 54.5% of the cases, the facial artery ended symmetrically. According to previous studies, variations in the distribution pattern of the facial artery have been regarded as racial difference. However, in this study we showed that the diverse pattern of the facial artery distribution demonstrates individual variation rather than racial difference. The superior and inferior labial arteries on the right side were more dominant than those on the left. The average distance between the branching points for the inferior alar branch and for the lateral nasal branch was 15.9 mm, and it was 25.2 mm between the points for the superior labial branch and for the inferior alar branch. The branching point of the inferior labial branch was 30.9 mm apart on average from that of the superior labial branch. The courses of the facial arteries showed no significant differences based on either laterality or gender.

Topographical anatomy on the communicating branch between the spinal accessory nerve and the anterior root of the first cervical nerve

The aim of this study was to clarify the morphological characteristics of the communicating branch between the spinal accessory nerve and the anterior root of the first cervical nerve (McKenzie branch), a structure severed during intradural selective rhizotomy for treatment of spasmodic torticollis. The right and left sides of 50 upper cervical segments of spinal cords were dissected and examined under a surgical microscope. Seven of the total 100 samples were found to have the McKenzie branch. Two types of McKenzie branch, which run close to the vertebral artery, were also identified, which might be helpful for improving the surgical results of intradural selective rhizotomy.

Inhibitory effects of the root cortex of Paeonia suffruticosa on interleukin-8 and macrophage chemoattractant protein-1 secretions in U937 cells

In an effort to elucidate the mechanism of the anti-inflammatory effect of mudanpi, the root cortex of Paeonia suffruticosa Andrews (Ranunculaceae), we determined the effects of the methanolic extract of mudanpi (MEM) on the secretions of interleukin (IL)-8, a major mediator of acute neutrophil-mediated inflammation, and macrophage chemoattractant protein (MCP)-1, a major mediator of chronic macrophage-mediated inflammation, in human monocytic U937 cells stimulated with phorbol myristate acetate (PMA). MEM significantly inhibited PMA-induced secretions of IL-8 and MCP-1 proteins in a dose-dependent manner. The inhibition of these chemokines by MEM was due to its suppression of IL-8 and MCP-1 genes. In addition, 1,2,3,4,6-penta-O-galloyl-beta-D-glucose, one of major constituents isolated from MEM, inhibited PMA-induced secretions of IL-8 and MCP-1 proteins by its suppression of IL-8 and MCP-1 genes. Thus, one possible anti-inflammatory mechanism of mudanpi, an anti-inflammatory Chinese crude drug, may be to inhibit the secretions of inflammatory chemokines.

Emerging patterns of the cervical cutaneous nerves in Asians

Numerous reports exist upon clinical viewpoints of the four cervical cutaneous nerves. Unfortunately, a detailed description of the cervical cutaneous nerves has not yet been published. For this reason, administering effective anaesthesia to a particular nerve branch is difficult. The aim of this study was to clarify the anatomical knowledge about the emerging patterns of the cervical cutaneous nerves in the superficial neck using 35 Korean cadavers (22 male, 13 female). Four cervical cutaneous nerve branches penetrating the fascia of the posterior border of the sternocleidomastoid muscle (SCM) were classified into seven types based on the locations of their nerve emergence. Among these, the separated type (L-G-T-S) was the most frequent (50%). followed by the L-G x T-S type (20.3%), in which the great auricular nerve (G) and the transverse cervical nerve (T) emerged at the same level on the posterior SCM border.

The membrane proteins, Spt23p and Mga2p, play distinct roles in the activation of Saccharomyces cerevisiae OLE1 gene expression. Fatty acid-mediated regulation of Mga2p activity is independent of its proteolytic processing into a soluble transcription activator

The Saccharomyces OLE1 gene encodes the Delta-9 fatty acid desaturase, an enzyme that converts saturated fatty acyl-CoAs into cis-Delta-9 unsaturated fatty acids. OLE1 gene expression is regulated by unsaturated fatty acids, which repress transcription and destabilize the OLE1 mRNA. Expression of OLE1 is activated by N-terminal proteolytic fragments of two homologous endoplasmic reticulum membrane proteins, Spt23p and Mga2p. Disruption of either gene does not significantly affect cell growth or fatty acid metabolism; cells that contain null alleles of both genes, however, are unsaturated fatty acid auxotrophs. An analysis of spt23Delta and mga2Delta strains shows that Spt23p and Mga2p differentially activate and regulate OLE1 transcription. In glucose-grown cells, both genes activate transcription to similar levels of activity. Expressed alone, Mga2p induces high levels of OLE1 transcription in cells exposed to cobalt or grown in glycerol-containing medium. Spt23p expressed alone activates OLE1 transcription to levels similar to those in wild type cells. OLE1 expression is strongly repressed by unsaturated fatty acids in spt23Delta or mga2Delta cells, under all growth conditions. To test if OLE1 expression is controlled by fatty acids at the level of membrane proteolysis, soluble N-terminal fragments of Spt23p and Mga2p that lack their membrane-spanning regions (Deltatm) were expressed under the control of their native promoters in spt23Delta;mga2Delta cells. Under those conditions, Mga2pDeltatm acts as a powerful transcription activator that is strongly repressed by unsaturated fatty acids. By comparison, the Spt23pDeltatm polypeptide weakly activates transcription and shows little regulation by unsaturated fatty acids. Co-expression of the two soluble fragments results in activation to levels observed with the Mga2pDeltatm protein alone. The fatty acid repression of transcription under those conditions is attenuated by Spt23Deltatm, however, suggesting that the two proteins may interact to modulate OLE1 gene expression.

Intradural anastomoses between the accessory nerve and the posterior roots of cervical nerves: their clinical significance

This study was performed to identify the anastomoses between the accessory nerve and the posterior roots of cervical nerves below the level of C1 segment, and to evaluate their clinical significance. One hundred spinal cord sides of Koreans were studied under the surgical microscope. In order to trace the posterior root of a cervical nerve after anastomosis with the accessory nerve, or the bridging fibers between the accessory nerve and the cervical posterior roots, the accessory nerves with the posterior roots and the bridging fibers were stained with osmium tetroxide. The anastomosis was classified into five types, according to whether the accessory nerve and the cervical posterior root crossed each other, and also according to the site of the bridging fiber between them. The bridging fibers in the most common type of anastomoses were observed to connect the posterior roots of a cervical nerve with the spinal rootlet of the accessory nerve. The possibility that the motor fibers of accessory nerve from the spinal cord may innervate the trapezius muscle through the cervical nerve, was discussed.

Modular fluorescence sensors for saccharides

Modular and modular polymer supported fluorescence photoinduced electron transfer (PET) sensors 2 and 3 with two boronic acid receptor units, a pyren-1-yl fluorophore, and hexamethylene linker show selective saccharide binding in aqueous methanolic solution at pH 8.21.

Anatomical study of the accessory head of the flexor pollicis longus and the anterior interosseous nerve in Asians

Anterior interosseous nerve palsy is known to occur uncommonly due to the compression of the nerve by the accessory head of flexor pollicis longus (AHFPL). This study was conducted to investigate the prevalence and origin of the AHFPL and the topographical relationship between the AHFPL and the anterior interosseous nerve in Asians. The AHFPL was present in 48 of 72 arms examined (66.7%), a majority of which originated from the coronoid process. The anterior interosseous nerve was observed to arise from both the medial and posterior aspects of the median nerve. The topographical relationship between the anterior interosseous nerve and the AHFPL was classified into three types depending on if the anterior interosseous nerve crossed the muscular part, or the tendinous part of the AHFPL, or coursed lateral to the AHFPL. The case in which the anterior interosseous nerve crossed the muscular part of the AHFPL occurred most frequently in the current study. The types in which the anterior interosseous nerve may be compressed were also discussed.

Tsc13p is required for fatty acid elongation and localizes to a novel structure at the nuclear-vacuolar interface in Saccharomyces cerevisiae

The TSC13/YDL015c gene was identified in a screen for suppressors of the calcium sensitivity of csg2Delta mutants that are defective in sphingolipid synthesis. The fatty acid moiety of sphingolipids in Saccharomyces cerevisiae is a very long chain fatty acid (VLCFA) that is synthesized by a microsomal enzyme system that lengthens the palmitate produced by cytosolic fatty acid synthase by two carbon units in each cycle of elongation. The TSC13 gene encodes a protein required for elongation, possibly the enoyl reductase that catalyzes the last step in each cycle of elongation. The tsc13 mutant accumulates high levels of long-chain bases as well as ceramides that harbor fatty acids with chain lengths shorter than 26 carbons. These phenotypes are exacerbated by the deletion of either the ELO2 or ELO3 gene, both of which have previously been shown to be required for VLCFA synthesis. Compromising the synthesis of malonyl coenzyme A (malonyl-CoA) by inactivating acetyl-CoA carboxylase in a tsc13 mutant is lethal, further supporting a role of Tsc13p in VLCFA synthesis. Tsc13p coimmunoprecipitates with Elo2p and Elo3p, suggesting that the elongating proteins are organized in a complex. Tsc13p localizes to the endoplasmic reticulum and is highly enriched in a novel structure marking nuclear-vacuolar junctions.

Characteristics of particle-loaded monolithic sol-gel columns for capillary electrochromatography. I. Structural, electrical and band-broadening properties

Particle-loaded (3 microm, C18) monolithic sol-gel columns have been prepared and selected characteristics measured. They have a surprisingly high permeability, allowing their operation in the microLC mode at pressures as low as 69 kPa where their efficiency is about 50000 plates per meter and the CEC mode where efficiency is at least 106000 plates per meter. These columns can withstand over 13.8 MPa pressure without compression or movement within the 75 microm capillary. Field strengths in the packed segments are approximately 50% greater than those in the open segments, due to the higher resistivity of the particle-laden regions. There is a relatively rapid loss of efficiency with increasing linear velocity in both the CEC and microLC modes, which may be due to a tortuosity effect in the inter- and intra-particulate voids. Chromatographic behavior is characteristic of conventional C18 particles, indicating that analytes have significant access to the surface within the pores of the immobilized bonded phase.

Arterial supply of the nasal tip in Asians

OBJECTIVES

The blood supply to the nasal tip and columella was examined to determine whether it could be damaged as a result of transcolumellar incision during an external rhinoplasty approach in Asians.

METHODS

The blood vessels that supply the nasal tip were examined by dissecting 51 cadavers, and their corresponding 102 nasal sections were injected with red latex before dissection. The size and distribution of the vessels were measured with the unaided eye and the primary supply vessels were determined. The subdermal layer in which the vessels lie and the course of the vessels were also investigated.

RESULTS

The main blood supply source of the nasal tip proved to be the lateral nasal artery in 78% (80/102) of the cases examined, while the remaining cases (22%) received their blood supply via the dorsal nasal artery. Columellar branches were narrow in diameter and varied in size and appearance, and were therefore appeared insufficient as a main blood supply. These arteries passed through the musculoaponeurotic layer, but they were also in close proximity to the main surgical plane in the dome of the lower lateral cartilage.

CONCLUSIONS

The authors speculate that the nasal tip blood supply in Asians is primarily derived from the lateral nasal or dorsal nasal arteries, with a variable contribution from the columella arteries. Therefore, it is important to correctly determine the surgical plane below the musculoaponeurotic layer in order to prevent skin flap necrosis or nasal tip deformity that may occur from damage to the main vessel during an external rhinoplasty approach.

Fontanelle and uncinate process in the lateral wall of the human nasal cavity

OBJECTIVES

Although a complete anatomic knowledge of the fontanelle is a prerequisite to perform a surgical antrostomy opening, little is known about the boundary, shape, and size of the fontanelle. The purpose of this paper is to determine the best site for maintaining the patency of a surgical antrostomy opening by defining the anatomic boundaries, shape, and size of the fontanelle as well as its histological structure.

MATERIALS AND METHODS

One hundred sagittally divided heads were utilized. Mucosa overlying the lateral nasal wall was carefully removed with an operating microscope under 6x magnification. In some cases, a double mucous membrane, including the posteroinferior portion of the uncinate process, was cut as a whole and embedded in paraffin. The sections were stained with H&E.

RESULTS

The boundary of the fontanelle and the location of the natural ostium were described in detail. Eight patterns of the posteroinferior portion of the uncinate process were observed. There were three major fontanelle shapes when observed from the medial aspect to the lateral: triangular, pencil-like, and oval. The triangular type was the most common. The anterior portion of the fontanelle was shorter than the posterior when observed medially and was wider than the posterior portion when observed inferiorly.

CONCLUSIONS

The anterior portion of the fontanelle is more prone to stenosis than the posterior portion. An antrostomy in the posterior fontanelle may be more ideal for a middle meatal antrostomy of the maxillary sinus.

Genotoxicity of paraquat: micronuclei induced in bone marrow and peripheral blood are inhibited by melatonin

The ability of melatonin to influence paraquat-induced genotoxicity was tested using micronucleated polychromatic erythrocytes as an index of damage in both bone marrow and peripheral blood cells of mice. Melatonin (10 mg/kg) or an equal volume of saline were administered intraperitoneally (ip) to mice 30 min prior to an ip injection of paraquat (20 mg/kgx2), and thereafter at 6-h intervals until the conclusion of the study (72 h). The number of the micronucleated polychromatic erythrocytes increased after paraquat administration both in peripheral blood and bone marrow cells. Melatonin administration to paraquat-treated mice significantly reduced micronuclei formation in both peripheral blood and bone marrow cells; these differences were apparent at 24, 48 and 72 h after paraquat administration. The induction of micronuclei was time-dependent with peak values occurring at 24 and 48 h. The reduction in paraquat-related genotoxicity by melatonin is likely due in part to the antioxidant activity of the indole. We did not observe effects of melatonin over paraquat in paraquat+melatonin groups incubated at 0, 60 and 120 min. Mitomycin C, which was used as a positive control, also caused the expected large rises in micronuclei in both bone marrow and peripheral blood cells at 24, 48 and 72 h after its administration.

Synthesis of [99mTc]ethylenedicysteine-colchicine for evaluation of antiangiogenic effect

Angiogenesis is in part responsible for tumor growth and the development of metastasis. Radiolabeled angiongenesis inhibitors would be useful to assess tumor microvasculature density. Colchicine (COL), a potent antiangiogenic agent, is known to inhibit microtubule polymerization and cell arrest at metaphase. This study aimed to develop 99mTc-labeled COL (EC-COL) using ethylenedicysteine (EC) as a chelator to assess tumor microvascular density. EC was conjugated to trimethylcolchicinic acid using N-hydroxysuccinimide and 1-ethyl-3-dimethylaminopropyl carbodiimide as coupling agents with a yield of 50-60%. In vivo stability was analyzed in rabbit serum at 0.5-4 h. Tissue distribution and planar imaging studies of [99mTc]EC-COL were evaluated in breast tumor-bearing rats at 0.5, 2 and 4 h. The data was compared to that using [99mTc]EC (control). The radiochemical yield of [99mTc]EC-COL was greater than 95%. [99mTc]EC-COL was stable in rabbit serum. In vivo biodistribution of [99mTc]EC-COL in breast tumor-bearing rats showed increased tumor-to-blood (0.52+/-0.12 to 0.72+/-0.07) and tumor-to-muscle (3.47+/-0.40 to 7.97+/-0.93) ratios as a function of time. Conversely, tumor-to-blood values showed a time-dependent decrease with [99mTc]EC over the same time period. Planar images confirmed that the tumors could be visualized clearly with [99mTc]EC-COL from 0.5 to 4 h. [99mTc]EC-COL may be useful to assess antiangiogenic and therapeutic effects during chemotherapy.

Polyelectroylte complex composed of chitosan and sodium alginate for wound dressing application

Drug-impregnated polyelectrolyte complex (PEC) sponge composed of chitosan and sodium alginate was prepared for wound dressing application. The morphological structure of this wound dressing was observed to be composed of a dense skin outer layer and a porous cross-section layer by scanning electron microscopy (SEM). Equilibrium water content and release of silver sulfadiazine (AgSD) could be controlled by the number of repeated in situ PEC reactions between chitosan and sodium alginate. The release of AgSD from AgSD-impregnated PEC wound dressing in PBS buffer (PH = 7.4) was dependent on the number of repeated in situ complex formations for the wound dressing. The antibacterial capacity of AgSD-impregnated wound dressing was examined in agar plate against Pseudomonas aeruginosa and Staphylococcus aureus. From the behavior of antimicrobial release and the suppression of bacterial proliferation, it is thought that the PEC wound dressing containing antimicrobial agents could protect the wound surfaces from bacterial invasion and effectively suppress bacterial proliferation. In the cytotoxicity test, cellular damage was reduced by the controlled released of AgSD from the sponge matrix of AgSD-medicated wound dressing. In vivo tests showed that granulation tissue formation and wound contraction for the AgSD plus dihydroepiandrosterone (DHEA) impregnated PEC wound dressing were faster than any other groups.

Noninvasive assessment of tumor hypoxia with 99mTc labeled metronidazole

PURPOSE

The assessment of tumor hypoxia by imaging modality prior to radiation therapy would provide a rational means of selecting patients for treatment with radiosensitizers or bioreductive drugs. This study aimed to develop a 99mTc-labeled metronidazole (MN) using ethylene-dicysteine (EC) as a chelator and evaluate its potential use to image tumor hypoxia.

METHODS

EC was conjugated to amino analogue of MN using Sulfo-N-hydroxysuccinimide and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide-HCl as coupling agents, the yield was 55%. Tissue distribution of 99mTc-EC-MN was determined in breast tumor-bearing rats at 0.5, 2, and 4 hrs. Planar imaging and whole-body autoradiograms were performed. The data was compared to that using 99mTc-EC (control), [18F]fluoromisonidazole (FMISO) and [(131)I] iodomisonidazole (IMISO).

RESULTS

In vivo biodistribution of 9mTc-EC-MN in breast tumor-bearing rats showed increased tumor-to-blood and tumor-to-muscle ratios as a function of time. Conversely, tumor-to-blood values showed time-dependent decrease with 9mTc-EC in the same time period. Planar images and autoradiograms confirmed that the tumors could be visualized clearly with 99mTc-EC-MN from 0.5 to 4 hrs. There was no significant difference of tumor-to-blood count ratios between 99mTc-EC-MN and [(131)I]IMISO at 2 and 4 hrs postinjection. From 0.5 to 4 hrs, both 9mTc-EC-MN and [(131)I]MISO have higher tumor-to-muscle ratios compared to [18]FMISO.

CONCLUSIONS

It is feasible to use 9mTc-EC-MN to image tumor hypoxia.

Inhibition by fluoxetine of voltage-activated ion channels in rat PC12 cells

The effects of fluoxetine (Prozac) on voltage-activated K+, Ca2+ and Na+ channels were examined using the whole-cell configuration of the patch clamp technique in rat pheochromocytoma (PC12) cells. When applied to the external bath solution, fluoxetine (1, 10, 100 microM) decreased the peak amplitude of K+ currents. The K+ current inhibition by fluoxetine (10 microM) was voltage-independent and the fraction of current inhibition was 39.7-51.3% at all voltages tested (0 to +50 mV). Neither the activation and inactivation curves nor the reversal potential for K+ currents was significantly changed by fluoxetine. The inhibition by fluoxetine of K+ currents was use- and concentration-dependent with an IC50 of 16.0 microM. The inhibition was partially reversible upon washout of fluoxetine. The action of fluoxetine was independent of the protein kinases, because the protein kinase C or A inhibitors (H-7, staurosporine, Rp-cAMPS) did not prevent the inhibition by fluoxetine. Intracellular infusion with GDPbetaS or pretreatment with pertussis toxin did not block the inhibitory effects of fluoxetine. The inhibitory action of fluoxetine was not specific to K+ currents because it also inhibited both Ca2+ (IC50 = 13.4 microM) and Na+ (IC50 = 25.6 microM) currents in a concentration-dependent manner. Our data indicate that when applied to the external side of cells, fluoxetine inhibited voltage-activated K+, Ca2+ and Na+ currents in PC12 cells and its action on K+ currents does not appear to be mediated through protein kinases or G proteins.

Melatonin enhances tamoxifen's ability to prevent the reduction in microsomal membrane fluidity induced by lipid peroxidation

The indoleamine melatonin and the synthetic antiestrogenic drug tamoxifen seem to have similar mechanisms in inhibiting the growth of estrogen receptor positive breast cancer cells. In this study, we compared the ability of these molecules, alone and in combination, in stabilizing microsomal membranes against free radical attack. Hepatic microsomes were obtained from male rats and incubated with or without tamoxifen (50-200 microM), melatonin (1 mM) or both; lipid peroxidation was induced by addition of FeCl3, NADPH and ADP. After oxidative damage, membrane fluidity, measured by fluorescence polarization techniques, decreased whereas malonaldehyde (MDA) and 4-hydroxyalkenals (4-HDA) concentrations increased. Incubation of the microsomes with tamoxifen prior to exposure to free radical generating processes inhibited, in a dose-dependent manner, the increase in membrane rigidity and the rise in MDA + 4-HDA levels. When melatonin was added, the efficacy of tamoxifen in preventing membrane rigidity was enhanced. Thus, the IC50s for preventing membrane rigidity and for inhibiting lipid peroxidation obtained for tamoxifen in the presence of melatonin were lower than those obtained with tamoxifen alone. Moreover, tamoxifen (50-200 microM) in the presence of melatonin reduced basal membrane fluidity and MDA + 4-HDA levels in microsomes. These synergistic effects of tamoxifen and melatonin in stabilizing biological membranes may be important in protecting membranes from free radical damage.

Melatonin in relation to cellular antioxidative defense mechanisms

Melatonin's actions in organisms are more widespread than originally envisaged. Over three decades ago, the changing pattern of nocturnal melatonin production was found to be the signal for the annual cycle of reproduction in photoperiodic species. Since then, melatonin's actions also have been linked to circadian rhythms, immune function, sleep, retinal physiology and endocrine functions in general. In recent years, however, the sphere of influence of melatonin was further expanded when the indole was found to be an effective free radical scavenger and antioxidant. Free radicals are toxic molecules, many being derived from oxygen, which are persistently produced and incessantly attack and damage molecules within cells; most frequently this damage is measured as peroxidized lipid products, carbonyl proteins, and DNA breakage or fragmentation. Collectively, the process of free radical damage to molecules is referred to as oxidative stress. Melatonin reduces oxidative stress by several means. Thus, the indole is an effective scavenger of both the highly toxic hydroxyl radical, produced by the 3 electron reduction of oxygen, and the peroxyl radical, which is generated during the oxidation of unsaturated lipids and which is sufficiently toxic to propagate lipid peroxidation. Additionally, melatonin may stimulate some important antioxidative enzymes, i.e., superoxide dismutase, glutathione peroxidase and glutathione reductase. In in vivo tests, melatonin in pharmacological doses has been found effective in reducing macromolecular damage that is a consequence of a variety of toxic agents, xenobiotics and experimental paradigms which induce free radical generation. In these studies, melatonin was found to significantly inhibit oxidative damage that is a consequence of paraquat toxicity, potassium cyanide administration, lipopolysaccharide treatment, kainic acid injection, carcinogen administration, carbon tetrachloride poisoning, etc., as well as reducing the oxidation of macromolecules that occurs during strenuous exercise or ischemia-reperfusion. In experimental models which are used to study neurodegenerative changes associated with Alzheimer's and Parkinson disease, melatonin was found to be effective in reducing neuronal damage. Its lack of toxicity and the ease with which melatonin crosses morphophysiological barriers and enters subcellular compartments are essential features of this antioxidant. Thus far, most frequently pharmacological levels of melatonin have been used to combat oxygen toxicity. The role of physiological levels of melatonin, which are known to decrease with age, is being investigated as to their importance in the total antioxidative defense capacity of the organism.

Melatonin and vitamin E limit nitric oxide-induced lipid peroxidation in rat brain homogenates

We have investigated the level of lipid peroxidation (LPO) in rat brain homogenates in the presence of nitric oxide (NO) which was released by the addition of sodium nitroprusside (SNP) and compared it with that induced by H2O2. We also examined the effect of melatonin and vitamin E on the NO-induced LPO. The concentration of malonaldehyde (MDA) plus 4-hydroxyalkenals (4-HDA) was used as an index of LPO. While both H2O2 and SNP increased MDA + 4-HDA production in brain homogenates in a concentration-dependent manner, SNP was more potent than H2O2 at all concentrations tested. Both melatonin or vitamin E reduced NO-induced LPO in a dose-dependent manner in concentrations ranging from 10 microM to 10 mM. Under the in vitro conditions of this experiment, vitamin E was more efficient than melatonin in limiting NO-induced LPO in rat brain homogenates.

ELO2 and ELO3, homologues of the Saccharomyces cerevisiae ELO1 gene, function in fatty acid elongation and are required for sphingolipid formation

ELO2 and ELO3 were identified from the Saccharomyces cerevisiae genome data base as homologues of ELO1, a gene involved in the elongation of the fatty acid 14:0 to 16:0. Mutations in these genes have previously been shown to produce pleiotropic effects involving a number of membrane functions. The simultaneous disruption of ELO2 and ELO3 has also been shown to produce synthetic lethality, indicating that they have related and/or overlapping functions. Gas chromatography and gas chromatography/mass spectroscopy analyses reveal that null mutations of ELO2 and ELO3 produce defects in the formation of very long chain fatty acids. Analysis of the null mutants indicates that these genes encode components of the membrane-bound fatty acid elongation systems that produce the 26-carbon very long chain fatty acids that are precursors for ceramide and sphingolipids. Elo2p appears to be involved in the elongation of fatty acids up to 24 carbons. It appears to have the highest affinity for substrates with chain lengths less than 22 carbons. Elo3p apparently has a broader substrate specificity and is essential for the conversion of 24-carbon acids to 26-carbon species. Disruption of either gene reduces cellular sphingolipid levels and results in the accumulation of the long chain base, phytosphingosine. Null mutations in ELO3 result in accumulation of labeled precursors into inositol phosphoceramide, with little labeling in the more complex mannosylated sphingolipids, whereas disruption of ELO2 results in reduced levels of all sphingolipids.

Melatonin prevents changes in microsomal membrane fluidity during induced lipid peroxidation

We tested the effect of melatonin on membrane fluidity in microsomes of a rat liver model in which lipid peroxidation was induced by the addition of FeCl3, ADP and NADPH. Membrane fluidity was monitored using fluorescence spectroscopy and lipid peroxidation was estimated by quantifying malonaldehyde (MDA)+4-hydroxyalkenals (4-HDA) concentrations following the induction of lipid peroxidation with and without pre-incubation with melatonin (1 microM-3 mM). Membrane rigidity increased during induced lipid peroxidation while melatonin reduced in a concentration-dependent manner both membrane rigidity and MDA+4-HDA generation. Melatonin's protective effect may relate to its known ability to scavenge free radicals and function as an antioxidant.

Cataractogenesis and lipid peroxidation in newborn rats treated with buthionine sulfoximine: preventive actions of melatonin

The purpose of this study was to examine the influence of exogenously administered melatonin on cataract formation and lipid peroxidation in newborn rats treated with buthionine sulfoximine (BSO), a drug which inhibits the rate-limiting enzyme in glutathione (GSH) synthesis, gamma-glutamylcysteine synthase, thereby depleting animals of their stores of the important intracellular antioxidant, GSH. BSO (3 mmol/kg BW) was given for three consecutive days beginning on postnatal day 2; melatonin (4 mg/kg) was injected daily beginning on postnatal day 2 and continuing until the animals were killed (either day 9 or day 17 after birth). None of the control animals (rats treated with neither BSO nor with melatonin) developed lenticular opacification during the observation period. In the BSO-treated rats, 16 of 18 animals (89%) had observable cataracts when they were examined. In rats that received both BSO and melatonin, the incidence of cataracts was highly significantly decreased, i.e., only 3 of 18 rats (7%) had observable cataracts. In addition to cataracts, the level of lipid peroxidation products (malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA)) was examined in the lens, brain, liver, lung, and kidney of control and experimental animals. In BSO-treated rats, the lens, kidney, and lung exhibited increased levels of MDA plus 4-HDA relative to those measured in the control rats; these increases were reversed in the BSO-treated rats who were injected with melatonin daily. While BSO administration did not increase basal levels of MDA plus 4-HDA in either the brain or liver, melatonin reduced levels of lipid peroxidation products below those measured in the control rats (at 17 days after birth). The changes induced by melatonin are consistent with the free-radical scavenging and antioxidative properties of this indole.

Melatonin Its intracellular and genomic actions

Besides its actions via membrane receptors on cells in specific areas of the brain and peripheral tissues, melatonin also has direct intracellular actions. The neurohormone melatonin is a potent free radical scavenger in vitro and a powerful antioxidant in vivo. Studies to date indicate that it is a better scavenger of the highly toxic hydroxyl and peroxyl radicals than some other known compounds. Melatonin also prevents the toxicity of singlet oxygen and stimulates the antioxidative enzyme, glutathione peroxidase. Considering its varied and potent antioxidant capability, it is possible that melatonin is an essential element of the antioxidant defense system of organisms. Besides these direct intracellular actions of melatonin, it was recently discovered that the indole also has binding sites in the nucleus of many cells. Melatonin's genomic actions are believed to follow its binding to these nuclear loci.

Genome organization of a partitivirus from the filamentous ascomycete Atkinsonella hypoxylon

We have identified viruses in several isolates of the filamentous ascomycete Atkinsonella hypoxylon. The virus from one isolate of the fungus, 2H, was selected for genomic characterization. Purified virus particles contained three dsRNAs with sizes estimated by gel electrophoresis to be 2.2, 2.1 and 1.8 kb. A library of cDNA clones representing the three dsRNA segments of isolate 2H was synthesized, mapped and sequenced. The three segments had no significant similarity to each other, as determined by Northern blot analysis, and had sizes of 2180, 2135 and 1790 nt as determined by nucleotide sequence analysis. Long open reading frames were deduced from the sequences of dsRNAs 1 (molecular mass 78 kDa) and 2 (74 kDa), but not from dsRNA 3. Both terminal regions of dsRNA 1 and dsRNA had similar nucleotide sequences, as determined from 5' RACE clones. Comparisons of the amino acid sequence deduced from dsRNA 1 revealed similarities with viral RNA-dependent RNA polymerases. Translation in vitro of full-length cDNA clones representing dsRNAs 1 and 2 each yielded single major products of > 70 kDa by analysis on polyacrylamide gels. Based on properties of its dsRNA segments, the virus of A. hypoxylon strain 2H fits into the Partitiviridae family, and represents the first member of this family from a fungal host completely characterized at the level of primary nucleotide sequence.

Expression of potyviral polyproteins in transgenic plants reveals three proteolytic activities required for complete processing

All proteins encoded by the plant potyvirus, tobacco etch virus (TEV), arise by proteolytic processing of a single polyprotein. Two virus-encoded proteinases (NIa and HC-Pro) that catalyze most of the proteolytic events have been characterized previously. The two proteins that are derived from the N-terminal 87 kd region of the viral polyprotein are a 35 kd protein and HC-Pro (52 kd). It is demonstrated in this study that a third proteolytic activity is required to process the junction between these proteins. Proteolysis at the HC-Pro N terminus to separate these proteins occurred poorly, if at all, after in vitro synthesis of a 97 kd polyprotein, whereas cleavage of the HC-Pro C terminus occurred efficiently by an autoprocessing mechanism. Synthesis of the same polyprotein in transgenic tobacco plants, however, resulted in complete and accurate proteolysis at both termini of HC-Pro. A point mutation affecting an amino acid residue essential for the proteolytic activity of HC-Pro had no effect on N-terminal processing. Expression in transgenic plants of a construct with a large deletion in the 35 kd protein coding region resulted in partial inhibition of HC-Pro N-terminal cleavage, suggesting that the 35 kd protein may affect the proteolytic event but not in a catalytic role. We speculate that this cleavage event is catalyzed by either a cryptic potyviral proteinase that requires a host factor or subcellular environment for activation, or possibly a host proteinase.

Identification of essential residues in potyvirus proteinase HC-Pro by site-directed mutagenesis

Two virus-encoded proteinases are responsible for proteolysis of potyvirus polyproteins. One of these, HC-Pro, is a multifunctional protein that autolytically cleaves at its carboxyl-terminus (J.C. Carrington et al., 1989, EMBO J. 8, 365-370). To identify the class of proteinase to which HC-Pro belongs, tobacco etch virus (TEV) HC-Pro mutants containing single amino acid substitutions at serine, cysteine, aspartic acid, and histidine positions were synthesized by in vitro transcription and translation and were tested for autoproteolytic activity. Combinations of these residues are constituents of the active sites of diverse groups of cellular and viral proteinases. Only those positions that were strictly conserved among four potyvirus HC-Pro proteolytic domains (for which sequences have been deduced) were mutagenized. Of the 19 mutant proteinases synthesized and tested, only those with alterations at Cys-649 and His-722 were defective for HC-Pro autolytic activity. Most of the other mutant proteinases exhibited no impairments in processing kinetics experiments. The spectrum of essential residues, as defined by this genetic analysis, supports the hypothesis that HC-Pro most closely resembles members of the cysteine-type family of proteinases.

Withdrawal of steroid immunosuppression in renal transplant recipients

The complications of long-term steroid immunosuppression are well known. During a 12-month period, 52 living-donor renal transplant recipients were entered into a protocol of intentional early steroid withdrawal. Selection criteria were primary living-related renal transplants in HLA-identical (12) or one-haplotype match (40) patients. The study population consisted of 25 diabetics (48.1%) with a mean age of 32.4 years. All patients received preoperative blood transfusions (3 donor-specific in haplotype-matched, 3 random in HLA-identical recipients). Immunosuppression consisted of cyclosporine, azathioprine, and corticosteroids, with deliberate steroid withdrawal after two weeks. Forty-six patients (88.5%) were successfully tapered off steroids, while the six protocol failures (11.5%) were due to early rejection or leukopenia that prevented steroid withdrawal. Twenty-three patients (50%) subsequently were returned to steroid therapy for rejection (21) or leukopenia (2). Inadequate immunosuppression precipitated six rejection episodes and were preventable, while the remaining 15 were true breakthrough crises. The overall rejection rate was 50%, with 92.3% of initial rejection episodes occurring within five weeks of steroid withdrawal. Rejection episodes were responsive to steroid therapy alone in 73.2% of cases. No graft loss from rejection has occurred after a mean follow-up interval of 8.5 months. At present, 33 patients (63.5%) are off steroids. In HLA-identical recipients, all but one successfully completed the protocol and 75% are currently steroid-free. In haplotype-matched patients, 87.5% completed the protocol and 60% are steroid-independent. Comparison with well-matched control groups on steroids failed to reveal any difference in graft or patient survival, rejection, infection, or mean serum creatinine level. No discriminating risk factors could be identified that were predictive of steroid withdrawal success or failure. In select patients, early steroid withdrawal can be accomplished without jeopardizing graft function. Long-term follow-up is required to assess the risk-benefit ratio of steroid withdrawal upon immunosuppressive morbidity.

Delayed response to orthoclone OKT3 treatment for renal allograft rejection resistant to steroid and antilymphocyte globulin

Since February 1986, 23 patients have received Orthoclone OKT3 treatment at our transplant center for renal allograft rejection resistant to steroids and antilymphocyte globulin (ALG). They have been followed for at least 4 months as of this study time (range: 4-15 months). We report here our experience with OKT3, including five late responders--as late as 116 days after OKT3 treatment. Overall rejection was reversed in 19/23 (83%). Rejection was controlled in 95% of primary and 50% of nonprimary transplants; 89% of the male and 80% of the female patients were treated successfully; 94% of the cadaver-donor and 80% of the living-donor transplants responded successfully. The one-year rerejection rate after OKT3 was 50%, and 38% of rerejection episodes were treated successfully. Time (days) required to reverse the episodes of acute graft rejection after the start of OKT3 is plotted, and it shows a distinctive bimodal distribution: first, early responders with a mean +/- SD of 12 +/- 5 days (range: 4-20 days) and second, late responders with a mean +/- SD of 58 +/- 31 days (range: 30-116 days). We conclude that OKT3 is very effective in treating steroid- and ALG-resistant acute rejection episodes, and also that it is important to be aware of the potential late response to OKT3 antirejection therapy and recommend delaying transplant nephrectomy or immunosuppressive withdrawal for as long as possible (probably up to 4 months) for patients who have received OKT3 treatment.

Kidney retransplantation in the cyclosporine era

The results of kidney retransplantation in the cyclosporine era remain to be determined. Over a 42-month period, 76 nonprimary renal transplants (66 second, 7 third, 3 fourth allografts) were performed in 73 recipients under cyclosporine immunosuppression. The patient population was predominantly white (90.4%) with a mean age of 32.3 years. Twenty-one recipients (28.8%) were diabetic, and 36 (49.3%) were highly sensitized (panel-reactive antibody [PRA] greater than 50%). Sixty-two patients received cadaver donor grafts while the remaining donations were living-related (12) or living-unrelated (2). A sequential antilymphocyte globulin/cyclosporine protocol was employed, with cyclosporine therapy delayed until adequate renal function occurred. Overall patient and graft survival is 92.1% and 60.5%, respectively, after a mean follow-up of 20.0 months. The mean serum creatinine is 1.64 mg/dl in the 46 functioning allografts. Graft survival is 63.6% for secondary grafts, 28.6% for tertiary grafts, and 66.7% for fourth kidney transplants. In second transplants, recipients of cadaver donor kidneys have a graft survival of 58.5%, while living-related donor graft survival is 84.6% (P = 0.07). In the cadaver retransplant population, duration of previous transplant function greater than one year and HLA-DR matching were associated with increased graft survival, while age over 39 and presence of diabetes mellitus with reduced graft survival. However, these trends were not significant. Peak PRA above 50% did demonstrate a significant negative impact on graft survival both in the univariate and multivariate analyses of risk factors. Acute rejection occurred in 50 patients (65.8%), and was successfully reversed 50% of the time. Of the 30 grafts lost, 25 (83.3%) occurred within four months of retransplantation. Transplant nephrectomy was performed in 20 patients. Cyclosporine was not administered in 21 (70%) of these early graft failures, negating any potential beneficial effect. Retransplantation can be performed safely, with living-donor graft survival superior to cadaver retransplant rates. Rejection and early graft loss are common, especially in the highly sensitized patient. The impact of cyclosporine immunosuppression in renal retransplantation is much less dramatic than in primary transplantation in a protocol that delays cyclosporine therapy until allograft function is demonstrated.

Increased infections associated with the use of OKT3 for treatment of steroid-resistant rejection in renal transplantation

We compared the infections encountered in 23 renal transplant patients given the monoclonal anti-T-cell antibody, Orthoclone OKT3 (OKT3), for treatment of steroid-resistant rejection in 1986 and in 23 control patients from 1984 to 1985 with resistant rejection matched demographically, for severity of rejection and for risk factors predisposing to infection, who did not receive OKT3; recipients of OKT3 received substantially less prednisone, cyclosporine, and antilymphocyte globulin (ALG) than control patients for treatment of the rejection episode. Fourteen (61%) patients given OKT3 developed one or more infections in the 3-month period following treatment as compared with 9 control patients (39%) given conventional antirejection therapy with high-dose steroids and, usually, ALG. Patients given OKT3 were significantly more likely to develop serious infections (pneumonia, bacteremia, meningitis, or severe viral infection; 16 episodes vs. 4, P = .02). Six recipients of OKT3 (26%) acquired infections typically encountered in states associated with depressed cell-mediated immunity (CMI)--Listeria sepsis (2), disseminated nocardiosis and Mycobacterium tuberculosis infection (1), cytomegalovirus (CMV) pneumonia (1), Yersinia infection with severe dermatophytosis (1), and Epstein-Barr virus-associated lymphoproliferative syndrome (1)--as compared with 1 case of mild CMV infection in the control group (P = .08). Trimethoprim-sulfamethoxazole (TMP-SMZ) was given to 19 patients in each group; all 4 recipients of OKT3 who did not receive TMP-SMZ prophylaxis developed life-threatening infection, 3, bacteremia (2 with Listeria) and 1, disseminated nocardiosis and M tuberculosis infection. These data suggest that OKT3 given for treatment of resistant rejection in renal transplantation predisposes the patient to serious infection, particularly with opportunistic pathogens characteristically associated with depressed cell-mediated immunity. Prophylaxis with TMP-SMZ, which is safe, well tolerated, and effective for reducing the incidence of infection in renal transplantation, may be especially important during OKT3 therapy.