Regulation of type II renal Na+-dependent inorganic phosphate transporters by 1,25-dihydroxyvitamin D3. Identification of a vitamin D-responsive element in the human NAPi-3 gene

Vitamin D is an important regulator of phosphate homeostasis. The effects of vitamin D on the expression of renal Na+-dependent inorganic phosphate (Pi) transporters (types I and II) were investigated. In vitamin D-deficient rats, the amounts of type II Na+-dependent Pi transporter (NaPi-2) protein and mRNA were decreased in the juxtamedullary kidney cortex, but not in the superficial cortex, compared with control rats. The administration of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) to vitamin D-deficient rats increased the initial rate of Pi uptake as well as the amounts of NaPi-2 mRNA and protein in the juxtamedullary cortex. The transcriptional activity of a luciferase reporter plasmid containing the promoter region of the human type II Na+-dependent Pi transporter NaPi-3 gene was increased markedly by 1,25-(OH)2D3 in COS-7 cells expressing the human vitamin D receptor. A deletion and mutation analysis of the NaPi-3 gene promoter identified the vitamin D-responsive element as the sequence 5'-GGGGCAGCAAGGGCA-3' nucleotides -1977 to -1963 relative to the transcription start site. This element bound a heterodimer of the vitamin D receptor and retinoid X receptor, and it enhanced the basal transcriptional activity of the promoter of the herpes simplex virus thymidine kinase gene in an orientation-independent manner. Thus, one mechanism by which vitamin D regulates Pi homeostasis is through the modulation of the expression of type II Na+-dependent Pi transporter genes in the juxtamedullary kidney cortex.

Effect of molecular architecture of hydrophobically modified poly(N-isopropylacrylamide) on the formation of thermoresponsive core-shell micellar drug carriers

Terminal-incorporation of hydrophilic or hydrophobic groups dramatically influences the phase transition of poly(N-isopropylacrylamide) (PIPAAm) because of a critical role of the polymer chain ends in initiation of the phase transition. Incorporation of an amino or hydroxyl group to one end of PIPAAm remarkably raised the LCST (lower critical solution temperature) and slowed down the rate of the phase transition, and these effects were more pronounced as the mole fraction of hydrophilic groups increased compared to the random copolymers of PIPAAm and hydrophilic co-monomers, such as acrylic acid (AAc) or dimethylacrylamide (DMAAm). Hydrophilic effects were more remarkable for hydroxyl groups, due to stronger hydrogen bonding with water. Terminal-modification (hydrophobization) was also more effective in producing hydrophobic effects on the PIPAAm phase transition in comparison with PIPAAm copolymers that were randomly modified along the main chain with hydrophobic co-monomers. Moreover, terminal-located hydrophobic groups were able to form hydrophobic microdomains that were clearly isolated from PIPAAm chains in aqueous media by the aggregation of hydrophobic segments. As a result, the obtained micellar aqueous solution showed the same LCST as pure PIPAAm, while the PIPAAm random copolymer with hydrophobic co-monomers formed incompletely separated microdomains. The LCST for this random copolymer was reduced with increasing hydrophobic co-monomer mole fraction. Hydrophobically terminal-modified PIPAAm produced thermo-responsive core-shell structures that exhibited the same LCST and the same thermal response rate as those of free linear PIPAAm chains. Such polymeric micellar structures show reversible thermoresponsive aggregation/dispersion and deformation/reformation in heating/cooling cycles through the LCST for pure PIPAAm. These properties indicate the possibility of using such a system as a thermoresponsive drug carrier with double targeting mechanisms, in both passive and active manners.

Polymeric micelles for drug delivery: solubilization and haemolytic activity of amphotericin B

Polymeric micelles may serve as nanoscopic, long-circulating carriers of hydrophobic drugs. In this study, we have researched the solubilization of amphotericin B (AmB), an antifungal drug, by micelles of poly(ethylene oxide)-block-poly(beta benzyl-L-aspartate) (PEO-PBLA), the properties of the AmB-loaded PEO-PBLA micelles and the resultant haemolytic activity of AmB. AmB loading takes place during self assembly of PEO-PBLA micelles, and this occurs through a dialysis procedure as an alkaline aqueous solution replaces the selective solvent for the polymer and the drug. In this way, AmB reaches levels of 57 to 141 microg/ml, corresponding to a loading efficiency of 27-30% (loaded AmB/initial amount of AmB). The molar ratio of AmB to PEO-PBLA is 0.40 to 1.0. Pictures by transmission electron microscopy reveal spherical AmB-loaded PEO-PBLA micelles with a mean diameter of 25.8+/-4.2 nm. AmB-loaded PEO-PBLA micelles are nonhaemolytic at an AmB level of 10 microg/ml as assessed by release of haemoglobin, measured by UV-Vis spectroscopy. AmB as Fungizone, its standard formulation, completely lyses red blood cells at a level of 3.0 microg/ml in 30 min. In contrast, there is no haemolysis at 5.5 h for AmB-loaded PEO-PBLA micelles at 3.0 microg/ml of AmB, indicating the gradual release of AmB from PEO-PBLA micelles. PEO-PBLA itself is nonhaemolytic even at a level of 0.70 mg/ml. Most amphiphiles, e.g. sodium deoxycholate, present in Fungizone, are haemolytic. Finally, AmB-loaded PEO-PBLA micelles can be freeze-dried and easily reconstituted in water. Afterwards, AmB is present in the intact PEO-PBLA micelles and remains nonhaemolytic.

Effect of phenylboronic acid groups in copolymers on endothelial cell differentiation into capillary structures

Copolymers (IABb) composed of N-isopropylacrylamide (I), N-(3-dimethylaminopropyl)-acrylamide (A), 3-acrylamidophenylboronic acid (B), and a hydrophobic comonomer, n-butyl methacrylate (b), were synthesized as cell culture substrata since we previously learned that bovine aortic endothelial cells (BAECs) cultured on the phenylboronic acid-containing copolymer (IAB) differentiated into capillary structures after 26 days culture. The synthesized IABb copo ymers contained higher boron and amine moieties than the IAB copolymer. The results of the dynamic contact angle measurement revealed that IABb copolymer-coated surfaces showed a relatively hydrophobic nature, changing to hydrophilic in response to the aqueous environment. BAECs cultured on the copolymer substrata developed into capillary networks after 7 days. This is probably due to the enrichment of boron and amine segments in the vicinity of the hydrophilic copolymer surface, enhancing more pronounced interaction of boronates with cell membrane glycocalyx. The introduction of n-butyl methacrylate into the polymers might enhance the diffusion of the hydrophobic segments to the bulk polymers and the concentration of relatively hydrophilic segments at the outermost polymer surfaces by contact with water. A copolymer (IAP) without boronic acid groups was also prepared using N-phenylacrylamide (P) as a comonomer instead of 3-acrylamidophenylboronic acid in the IAB copolymer to investigate the effect of boronic acid moieties on the capillary formation of the cultured cells. Although the endothelial cells seeded on the copolymer without boronic acid groups adhered during the early culture period, these cells showed neither proliferation nor differentiation and detached from the surface after 13 days. These results strongly support the opinion that the phenylboronic acid groups in the copolymers are responsible for the specific induction of tissue formation of BAECs through the interaction with glycoconjugates on the cell membranes.

Minimized platelet interaction with poly(2-hydroxyethyl methacrylate-block-4-bis(trimethylsilyl)methylstyrene) hydrogel showing anomalously high free water content

Novel hydrophilic-hydrophobic block copolymers - poly(2-hydroxyethyl methacrylate-block-4-bis(trimethylsilyl)methylstyrene) (poly(HEMA-block-BSMS) or BH polymer) - were prepared as materials potentially useful for blood-contacting devices. Among the BH(X) series including poly(HEMA) itself, platelet adhesion and activation are minimum on the surface of BH(10), the block copolymer composed of 10 mol% of the hydrophobic segment. The unique physicochemical characteristics of BH(10) such as the high free water content and the increased mobility of PHEMA segments seem to play an important role in the prevention of platelet adhesion and activation. The water content of BH(10) was twice that of poly(HEMA) itself, even in the presence of 10 mol% of the hydrophobic moiety [poly(BSMS)]. Further, an anomalous increase in free water content was observed for the BH(10) sample measured by DSC. The glass transition temperature of BH(10) in the dry state was determined to be c. 10 degrees C, which was much lower than that observed for each of the homopolymers (c.f.: Tg [poly(HEMA)] = 70 degrees C; Tg [poly(BSMS)] = 160 degrees C), suggesting an increased mobility of tethered PHEMA segments in the BH(10) film.

Identification of rhodopsin in the pigeon deep brain

We detected rhodopsin gene expression in the pigeon lateral septum, a photosensitive deep brain region that is responsible for the photoperiodic gonadal response. The nucleotide sequence of the deep brain rhodopsin cDNA clone exactly matched that of the retinal one, indicating that a single rhodopsin gene is transcribed in the two tissues. Immunohistochemical analysis localized rhodopsin in the cerebrospinal fluid-contacting neurons, which have been assumed to be photoreceptive cells in the deep brain. Pigeon rhodopsin seems to play dual important roles in the visual and non-visual systems, the latter of which contributes to the photoperiodic response.

A deep brain photoreceptive molecule in the toad hypothalamus

We have isolated a cDNA clone encoding a deep brain photoreceptive molecule from the hypothalamic cDNA library of the toad, Bufo japonicus. The deduced amino acid sequence showed the highest similarity to that of pinopsin (75-76%) among vertebrate retinal opsins, indicating the expression of toad pinopsin in the deep brain. Antibodies raised against the C-terminal tail of toad pinopsin stained cell bodies and the knob-like structures of the cerebrospinal fluid-contacting neurons in the anterior preoptic nucleus. This region is known to play an important role in breeding behavior, suggesting that toad pinopsin acts as a photosensor for the photoperiodic gonadal response.

Temperature-responsive size-exclusion chromatography using poly(N-isopropylacrylamide) grafted silica

Silica-based packing materials induce non-specific interactions with proteins in aqueous media because of the nature of their surface, mainly silanol groups. Therefore, the silica surface has to be modified in order to be used as stationary phase for the High Performance Size-Exclusion Chromatography (HPSEC) of proteins. For this purpose, porous silica beads were coated with hydrophilic polymer gels (dextrans of different molecular weights) carrying a calculated amount of diethyl-aminoethyl groups (DEAE). Actually, as shown by HPSEC, these dextran modified supports minimize non-specific adsorption for proteins and pullulans in aqueous solution. Then, in order to change the pore size in response to temperature, temperature responsive polymer of poly(N-isopropylacrylamide) (PIPAAm) was introduced into the surface of dextran-DEAE on porous silica beads. The structure of these supports before and after modification was alternately studied by Scanning Electronic Microscopy (SEM) and Scanning Force Microscopy (SFM). An adsorption of radiolabelled albumin was performed to complete our study. Silica modifications by dextran-DEAE and PIPAAm improve the neutrality of the support and minimize the non-specific interactions between the solid support and proteins in solution. At low temperature, the support having PIPAAm exhibits a high resolution domain in HPSEC and finally permits a better resolution of proteins and pullulans. At higher temperature, hydrophobic properties of PIPAAm produce interactions with some proteins and trigger off a slight delay of their elution time.

[Targeting of anticancer drug using intelligent polymers]

To fabricate the drug targeting system, it is very effective to combine passive targeting with intelligent polymeric system such as temperature-responsive polymers. We have been studying the passive targeting of anticancer drug bonded with or physically trapped in polymeric micelle derived from poly (ethylene oxide) (PEO) and poly (aspartic acid) block copolymer. On the other hand, Poly(N-isopropylacrylamide) (PIPAAm) is known to be a thermo-responsive polymer which has lower critical solution temperature (LCST, 32 degrees C). PIPAAm shows the reversible phase transition above and below LCST. Attempts to apply thermo-responsive drug carriers were made to enhance the site-specificity of polymeric micelle. Namely, novel type of polymeric micelle were prepared from block copolymers comprising N-isopropylacrylamide (IPAAm)-hydrophobic polymers. This temperature responsive micelles were expected to induce selective accumulation controlled by temperature modulation.

Light-dependent expression of pinopsin gene in chicken pineal gland

The phase of a circadian clock in the chicken pineal gland is reset by an environmental light signal, which is captured by the pineal photoreceptive molecule(s). Here we show that the mRNA level of pinopsin, a predominant photoreceptive molecule in the pineal gland, undergoes a diurnal fluctuation in chickens maintained on a light/dark cycle. The mRNA levels in the light were approximately six times higher than those in the dark. This fluctuation was not observed in constant darkness, where the mRNA levels remained low. Subsequent light exposure of chickens increased the amount of pinopsin mRNA regardless of the circadian time. Clearly, the expression of pinopsin gene is controlled by a light signal, independent of the circadian clock. In vitro experiments using cultured pineal glands isolated from the visual system also revealed the light-dependent increase in pinopsin mRNA level, indicating that the pineal photoreceptive molecule(s) is responsible for the induction. These results demonstrate the presence of a feedback loop through which the light signal captured by pinopsin stimulates the transcription of its own gene in the chicken pineal gland. In contrast, pinopsin protein remained at an almost constant level in chickens maintained under the same light/dark cycles. The protein level, however, decreased to approximately 50% of the light/dark level under constant darkness and subsequently increased upon exposure to light after the dark period. It is suggested that, under the light/dark cycles, the pinopsin protein level is kept constant by the light-dependent synthesis, which would compensate for a possible degradation of pinopsin in the daytime.

An epidemiological and clinical investigation of postpartum psychiatric illness in Japanese mothers

A case note study of postpartum psychiatric illness as defined by Research Diagnostic Criteria (RDC) was conducted in an epidemiologically defined large area of Japan. The admission rate was 0.34/1000 live births. The most frequent diagnostic category was affective disorder (53%). "Atypical" symptoms were observed in 31% of all cases and were more frequent (67%) in patients with schizoaffective disorder. Fifty six percent of mothers developed a psychiatric illness within two weeks of delivery. The patients with "atypical" symptoms were admitted much more quickly and their length of stay in hospital was shorter.

Burkitt's lymphoma involving the mandible: report of a case and review of Japanese cases

A Japanese case of Burkitt's lymphoma is presented. The intraoral and panoramic images showed alveolar bone destruction with an infiltrative border, displacement of lower molars, root resorption, and loss of lamina dura and the follicular cortex of a developing tooth, similar to descriptions in previous reports. Computed tomography revealed that a primary lesion occupied the mandible and extended to the muscles of facial expression and to the sublingual and submandibular spaces. Another soft tissue mass was evident in the contralateral parapharyngeal space. Results of a survey of the Japanese literature are also presented; they indicate differences in the clinical features between Japanese cases and African and American cases of Burkitt's lymphoma.

Characterization of physical entrapment and chemical conjugation of adriamycin in polymeric micelles and their design for in vivo delivery to a solid tumor

An anticancer drug adriamycin (ADR) was incorporated into polymeric micelles forming from poly(ethylene glycol)-poly(aspartic acid) block copolymer by chemical conjugation and physical entrapment. Structural stability of the polymeric micelles was found to be dependent on both the contents of chemically conjugated and physically entrapped ADR. The polymeric micelle with high contents of the chemically conjugated ADR and the physically entrapped ADR expressed very high in vivo antitumor activity against murine C 26 tumor, while the polymeric micelle with only the chemically conjugated ADR showed negligible in vivo activity. This indicates that the physically entrapped ADR played a major role in antitumor activity in vivo. For the polymeric micelle with the high ADR contents, it was found that a dimer of adriamycin molecules formed and that this dimer was physically entrapped in the inner core of the micelle as well as intact ADR.

Nuclear factor of activated T cells (NFAT) as a molecular target for 1alpha,25-dihydroxyvitamin D3-mediated effects

The molecular basis of the immunomodulatory properties of 1alpha,25-dihydroxyvitamin D3 (1alpha,25(OH)2D3) remains elusive. We demonstrate here that 1alpha,25(OH)2D3-mediated suppressive effects on the inducible expression of cytokine genes in human T cells may, in part, be due to diminished activity of the transcription factor NFAT. The vitamin D3 receptor (VDR) and its heterodimeric partner retinoid X receptor alpha (RXR alpha) specifically bound to the distal NFAT site in the human IL-2 promoter, and this binding was abolished by mutating unique regions in the NFAT oligonucleotide. In vitro inhibition of NFAT complex formation was noted when VDR-RXR alpha heterodimers were added to DNA binding reactions containing nuclear extracts from activated B or T cells, whereas in vitro NFkappaB complex formation was not significantly influenced. Furthermore, 1alpha,25(OH)2D3 treatment of activated T cells resulted in decreased formation of NFAT complexes detected upon incubation of nuclear extracts from these cells with 32P-labeled probe. Transient expression of both VDR and RXR alpha, but not of a single component, was capable of inhibiting expression of a NFAT-driven reporter gene in stimulated jurkat cells in a ligand-dependent manner. These results suggest that NFAT plays a crucial role in 1alpha,25(OH)2D3-mediated immunosuppressive activity.

Tissue engineered skeletal muscle: preparation of highly dense, highly oriented hybrid muscular tissues

We prepared highly dense, highly oriented hybrid muscular tissues that are composed of C2C12 cells (skeletal muscle myoblast cell line) and type I collagen. A cold mixture of C2C12 cells suspended in DMEM and type I collagen solution was poured into capillary tube molds of two different sizes (inner diameters; 0.90 and 0.53 mm, respectively). One end of each mold was sealed. Upon centrifugation (1000 rpm, 5 min) and subsequent thermal gelation, a rod-shaped gel was obtained. It was cultured in an agarose gel-coated dish for 7 days (first for 3 days in a growth medium and then for 4 days in a differentiation medium), during which time it shrank to become a highly dense tissue. Small-diameter rod-shaped, highly dense cellular assemblages with multinucleated myotubes were formed and only few necrotic cells at the core of the tissue were observed. On the other hand, a ring-shaped tissue prepared using a specially devised agarose gel mold was subjected to cyclic stretching at 60 rpm, resulting in the formation of a highly dense, highly oriented hybrid muscular tissue in which both densely accumulated cells and collagen fiber bundles tended to be aligned in the direction of stretching. The hybrid muscular tissues that were prepared using via sequential procedures of a centrifugal cell packing method and a mechanical stress-loading method became closer to native muscular tissues in terms of cell density and orientation.

Orthotopic ossification of the spinal ligaments of Zucker fatty rats: a possible animal model for ossification of the human posterior longitudinal ligament

Ossification of the posterior longitudinal ligament is a human genetic disease in which pathological ectopic ossification of the spinal ligaments develops. This leads to myelopathy or radiculopathy due to compression of the spinal cord. In this study, we investigated the histological features of orthotopic ossification of the spinal ligaments of senile Zucker fatty rats. A remarkably high incidence of orthotopic ossification was observed mainly in the thoracic spinal ligaments as compared with controls. The histopathological findings were similar to those for ossification of the human posterior longitudinal ligament. Bone morphogenetic proteins and activins, which exert their effects by way of specific type-I and type-II serine/threonine kinase receptors, play important roles in the formation of bone and cartilage. In the spinal ligaments of Zucker fatty rats, bone morphogenetic protein receptors and activin receptors were immunohistochemically detected around the ossified foci in a manner similar to that previously shown for the ossified tissue from patients who had ossification of the posterior longitudinal ligament. Thus, bone morphogenetic proteins and activin receptors might play important roles in orthotopic ossification of the spinal ligaments of Zucker fatty rats as well as in ossification of the posterior longitudinal ligament of humans. In addition, bone morphogenetic protein-receptor-IA was expressed in the nonossified ligament, suggesting that the spinal ligaments, of the rats may have a predisposition to orthotopic ossification. In the controls, no expression of bone morphogenetic protein receptors or of activin receptors was observed. In conclusion, there is a great degree of similarity between orthotopic ossification of the spinal ligaments of Zucker fatty rats and ossification of the posterior longitudinal ligament of humans. Thus, the rats provide a useful animal model for the study of ossification of the human posterior longitudinal ligament.

The effect of epidural saline injection on analgesic level during combined spinal and epidural anesthesia assessed clinically and myelographically

An epidural injection of physiological saline solution after spinal anesthesia may produce a higher level of analgesia than spinal anesthesia alone because of a volume effect. The purpose of this study was to clarify the volume effect caused by epidural injection of saline after spinal anesthesia. Twenty patients undergoing combined spinal and epidural anesthesia for elective surgery whose analgesic levels did not reach the surgical regions 10 min after spinal anesthesia at the L4-5 interspace were randomly assigned to two groups. The control group (n = 10) received no epidural saline injection. The saline group (n = 10) received 10 mL of saline through an epidural catheter at the L2-3 or L3-4 interspace 10 min after spinal anesthesia. In the saline group, the levels of analgesia 15 and 20 min after spinal anesthesia were significantly higher than those in the control group (P < 0.05). Next, we examined the volume effect of epidural injection of saline with myelography using two adult volunteers. In both volunteers, the upper level of the contrast medium, which was injected in the lumbar subarachnoid space, began to increase concurrently with lumbar epidural injection of saline, reaching from L3 to L1 and from L2 to T12. The diameter of the subarachnoid space diminished to less than 25% after injection of saline. We conclude that lumbar epidural injection of saline increases the analgesic level 10 min after spinal anesthesia, probably because of a volume effect.

IMPLICATIONS

In this study, using surgical patients and volunteers, we determined that a lumbar epidural injection of physiological saline solution 10 min after spinal anesthesia produces a higher analgesic level than spinal anesthesia alone because of a volume effect.

Immunocytochemical identification of pinopsin in pineal glands of chicken and pigeon

Pinopsin is a blue-sensitive photoreceptive molecule possibly involved in photic entrainment of the circadian pacemaker in the chicken pineal gland. To characterize pinopsin as a circadian photoreceptor, antibodies were raised against the C-terminal portion of pinopsin. As expected from the divergence of the amino acid sequence of this region, the resultant antibody cross-reacted with neither chicken rhodopsin nor red-sensitive cone pigment (chicken red). In Western blot analysis, the antibody stained a single band of 42-kDa protein in a detergent-extract of chicken pineal membranes, suggesting that pinopsin (calculated molecular weight, 38187) might be glycosylated and/or palmitoylated. Immunocytochemical examination of pineal sections of the chicken and the pigeon with this antibody revealed strong positive images for most of the membrane structures in the lumen of the follicles. This antibody also stained string- and bulb-shaped structures of the chicken parafollicular cells, the morphology of which resembles those of retinal photoreceptor cells. In contrast to the predominant distribution of pinopsin, a monoclonal antibody specific for chicken red stained a smaller number of membrane structures in the lumen of chicken pineal follicles. These results strongly suggest that the chicken pineal gland contains at least two types of photoreceptive molecules, pinopsin (major) and chicken red (minor). We show that the former molecule is localized in parafollicular pinealocytes and in the outer segments of pinealocytes that make contact with the follicular lumen.

Synthetic studies of vitamin D analogs. XXIV. Synthesis of active vitamin D3 analogs substituted at the 2 beta-position and their preventive effects on bone mineral loss in ovariectomized rats

Analogs related to 1 alpha,25-dihydroxy-2 beta-(3-hydroxypropoxy)vitamin D3 (ED-71) (4), oxa-type and carba-type analogs of vitamin D3 bearing substituents at the 2 beta-position of 1 alpha,25-dihydroxyvitamin D3 (1), were synthesized from the alpha-epoxides (6 and 13). Three analogs, ED-71 (4) and two carba-type analogs (16 and 26), showed potent preventive effects on bone mineral loss in pre-osteoporosis model rats. ED-71 (4) was concluded to be an optimized analog and a promising candidate for the treatment of osteoporosis.

Tissue engineering of skeletal muscle. Highly dense, highly oriented hybrid muscular tissues biomimicking native tissues

A highly dense, highly oriented hybrid muscular tissue was devised using C2C12 cells (skeletal muscle myoblast cell line) and Type I collagen. A cold mixture of C2C12 cells suspended in DMEM (Dulbecco's modified Eagle's medium; Gibco Lab Inc., Grand Island, NY) and Type I collagen solution was poured into capillary tube molds of two different sizes (inner diameters: 0.90 mm and 0.53 mm, respectively) sealed at each end. After centrifugation (1000 RPM, 5 min) and subsequent thermal gelation, a rod shaped gel was formed. The resultant gel shrank to become a highly dense tissue after incubation on an agarose gel coated dish. Small diameter rod shaped tissues were composed of numerous multi-nucleated myotubes and a few necrotic cells. On the other hand, a ring shaped tissue fabricated by centrifugation with a specially devised agarose gel mold was subjected to cyclic stretching at 60 RPM. The resultant highly dense, highly oriented hybrid muscular tissue involved both densely accumulated cells and collagen fiber bundles, which tended to be aligned in the direction of stretching. Sequential procedures of a centrifugal cell packing method and a mechanical stress loading method facilitated fabrication of hybrid muscular tissues similar to native muscular tissues in terms of cell density and orientation.

A new double lumen balloon catheter for retrograde cerebral perfusion via jugular vein cannulation

A new catheter for retrograde cerebral perfusion (RCP) was developed that can be used to deliver blood directly into the internal jugular vein (IJV) beyond the venous valves at the jugular-subclavian junction and prevent blood from draining into the lower half of the body. This catheter can be inserted into the IJV via a standard puncture technique by use of a 14 Fr sheath. The catheter shaft has two channels for balloon inflation and blood perfusion, respectively. A balloon for occlusion of drainage veins (superior vena cava and azygos vein) is installed at the catheter tip. Side holes, through which oxygenated cold blood is delivered into the IJV, are located 95 mm from the catheter tip. In a mock circulatory study, the pressure at the perfusion line (16-118 mmHg) increased with the increasing flow rate (0-400 ml/min). In clinical application, under circulatory arrest with profound hypothermia, inflation of the balloon effectively reduced blood drainage into the lower half of the body and, consequently, RCP was successfully performed (flow rate, 300-350 ml/min; pressure at the IJV, 15 mmHg). Because all of these procedures were controlled from outside the operative field, RCP by use of this catheter could be useful in distal arch replacement via left lateral thoracotomy.

Immunoelectron-microscopic investigation of the subcellular localization of pinopsin in the pineal organ of the chicken

Pinopsin is a photoreceptive molecule cloned from the chicken pineal organ. An antibody highly specific for pinopsin was applied in light- and electron-microscopic immunocytochemical studies of the pineal organ of 1 to 2-month-old chickens. Intense immunoreactivity was found in the follicular lumen at the light-microscopic level. In addition, small immunoreactive spherical or fibrous structures were diffusely distributed at the parafollicular aspect of the pineal organ. To identify immunoreactive elements precisely, we used pre-embedding immunoelectron microscopy. These studies revealed immunoreactive outer segments of pinealocytes arranged closely side by side in the follicular lumina. The thin initial portion of the outer segment arose from a basal body located in the inner segment. Immunoreactive pear-shaped outer segments occupied small lumina. Follicular lumina displayed immunonegative arrays of whorl-like lamellar membranes. Occasionally, these immunonegative structures were surrounded by immunoreactive concentric lamellar complexes. In the parafollicular pineal parenchyma, long slender cilium-like structures or enlarged cilia and concentric lamellar arrays showed intense immunoreactivity. All immunoreactive structures observed in this study were considered to represent outer segments of pinealocytes of the chicken pineal organ.

A novel high-performance liquid chromatographic assay for vitamin D metabolites using a coulometric electrochemical detector

A new, highly sensitive HPLC assay method using an electrochemical detector (ECD) for multiple assay of vitamin D metabolites is reported. The assay involves extracting lipids from plasma with methylene chloride and methanol, purification on Zorbax SIL column with 5.5% (v/v) iso-propanol in hexane and quantification by HPLC-ECD. A coulometric system, composed of the dual electrode analytical cell and a guard cell, was used for ECD of the eluting compounds. The potentials applied to detectors 1 and 2 in a dual electrode analytical cell were adjusted to +0.20 V and +0.60 V, respectively. This method is sensitive to 20 pg of 25-hydroxyvitamin D3 [25(OH)D3] and of 24R,25-dihydroxyvitamin D3 [24,25(OH)2D3]. Calibration curves gave linearity from 20-1000 pg for 25(OH)D3 and 24,25(OH)2D3. The detection limit was approximately 50 pg ml-1 for 25(OH)D3 and 24,25(OH)2D3 in plasma. This sensitivity combined with an overall recovery of 25(OH)D3 (81.5 +/- 2.6%, mean +/- S.E.) allows the measurement of trace amount of 25(OH)D3 with only 20 microliters of plasma. Intra- and interassay RSD values were 5.3 and 9.7% for 25(OH)D3 and 6.3 and 9.7% for 24,25(OH)2D3, respectively. Plasma levels of 25(OH)D3 and 24,25(OH)2D3 in normal adults were 15.9 +/- 2.8 ng ml-1 (n = 10) and 1.4 +/- 0.5 ng ml-1 (n = 10), respectively. This method allows the determination of 25(OH)D2 and 25(OH)D3 for evaluating their nutritional and clinical status. From these results, it is concluded that the proposed HPLC-ECD assay system is useful for the determination of vitamin D metabolites in biological fluids as a highly sensitive physicochemical method.