The natural killer T-cell ligand alpha-galactosylceramide prevents autoimmune diabetes in non-obese diabetic mice

Diabetes in non-obese diabetic (NOD) mice is mediated by pathogenic T-helper type 1 (Th1) cells that arise because of a deficiency in regulatory or suppressor T cells. V alpha 14-J alpha 15 natural killer T (NKT) cells recognize lipid antigens presented by the major histocompatibility complex class I-like protein CD1d (refs. 3,4). We have previously shown that in vivo activation of V alpha 14 NKT cells by alpha-galactosylceramide (alpha-GalCer) and CD1d potentiates Th2-mediated adaptive immune responses. Here we show that alpha-GalCer prevents development of diabetes in wild-type but not CD1d-deficient NOD mice. Disease prevention correlated with the ability of alpha-GalCer to suppress interferon-gamma but not interleukin-4 production by NKT cells, to increase serum immunoglobulin E levels, and to promote the generation of islet autoantigen-specific Th2 cells. Because alpha-GalCer recognition by NKT cells is conserved among mice and humans, these findings indicate that alpha-GalCer might be useful for therapeutic intervention in human diseases characterized by Th1-mediated pathology such as Type 1 diabetes.

Metal binding modes of Alzheimer's amyloid beta-peptide in insoluble aggregates and soluble complexes

Aggregation of the amyloid beta-peptide (Abeta) into insoluble fibrils is a key pathological event in Alzheimer's disease. Zn(II) induces the Abeta aggregation at acidic-to-neutral pH, while Cu(II) is an effective inducer only at mildly acidic pH. We have examined Zn(II) and Cu(II) binding modes of Abeta and their pH dependence by Raman spectroscopy. The Raman spectra clearly demonstrate that three histidine residues in the N-terminal hydrophilic region provide primary metal binding sites and the solubility of the metal-Abeta complex is correlated with the metal binding mode. Zn(II) binds to the N(tau) atom of the histidine imidazole ring and the peptide aggregates through intermolecular His(N(tau))-Zn(II)-His(N(tau)) bridges. The N(tau)-metal ligation also occurs in Cu(II)-induced Abeta aggregation at mildly acidic pH. At neutral pH, however, Cu(II) binds to N(pi), the other nitrogen of the histidine imidazole ring, and to deprotonated amide nitrogens of the peptide main chain. The chelation of Cu(II) by histidine and main-chain amide groups results in soluble Cu(II)-Abeta complexes. Under normal physiological conditions, Cu(II) is expected to protect Abeta against Zn(II)-induced aggregation by competing with Zn(II) for histidine residues of Abeta.

Hormonal induction of all stages of spermatogenesis in vitro in the male Japanese eel (Anguilla japonica)

The importance of gonadotropins and androgens for spermatogenesis is generally accepted in vertebrates, but the role played by specific hormones has not been clarified. Under cultivation conditions, male Japanese eels (Anguilla japonica) have immature testes containing only premitotic spermatogonia, type A and early-type B spermatogonia. In the present study, a recently developed organ-culture system for eel testes was used to determine in vitro effects of various steroid hormones on spermatogenesis. After 9 days of culture in serum-free, chemically defined medium containing 11-ketotestosterone (10 ng/ml), a major androgen in male eels, type A and early-type B spermatogonia began mitosis, producing late-type B spermatogonia. After 18 days, zygotene spermatocytes with synaptonemal complexes appeared, indicating that meiosis had already started by this time. In testis fragments cultured for 21 days, round spermatids and spermatozoa were observed with spermatogenic cells at all stages of development. Addition of 11-ketotestosterone to the culture medium also caused a marked cytological activation of Sertoli cells. No other steroid hormones tested had such stimulatory effects. These results, together with our earlier observations, suggest the following sequence for the hormonal induction of spermatogenesis in eel testes; gonadotropin stimulates the Leydig cells to produce 11-ketotestosterone, which, in turn, activates the Sertoli cells leading to the completion of spermatogenesis. This is, thus, an example of an animal system in which all stages of spermatogenesis have been induced by hormonal manipulation in vitro.

Rational design of fluorescein-based fluorescence probes. Mechanism-based design of a maximum fluorescence probe for singlet oxygen

Fluorescein is one of the best available fluorophores for biological applications, but the factors that control its fluorescence properties are not fully established. Thus, we initiated a study aimed at providing a strategy for rational design of functional fluorescence probes bearing fluorescein structure. We have synthesized various kinds of fluorescein derivatives and examined the relationship between their fluorescence properties and the highest occupied molecular orbital (HOMO) levels of their benzoic acid moieties obtained by semiempirical PM3 calculations. It was concluded that the fluorescence properties of fluorescein derivatives are controlled by a photoinduced electron transfer (PET) process from the benzoic acid moiety to the xanthene ring and that the threshold of fluorescence OFF/ON switching lies around -8.9 eV for the HOMO level of the benzoic acid moiety. This information provides the basis for a practical strategy for rational design of functional fluorescence probes to detect certain biomolecules. We used this approach to design and synthesize 9-[2-(3-carboxy-9,10-dimethyl)anthryl]-6-hydroxy-3H-xanthen-3-one (DMAX) as a singlet oxygen probe and confirmed that it is the most sensitive probe currently known for (1)O(2). This novel fluorescence probe has a 9,10-dimethylanthracene moiety as an extremely fast chemical trap of (1)O(2). As was expected from PM3 calculations, DMAX scarcely fluoresces, while DMAX endoperoxide (DMAX-EP) is strongly fluorescent. Further, DMAX reacts with (1)O(2) more rapidly, and its sensitivity is 53-fold higher than that of 9-[2-(3-carboxy-9,10-diphenyl)anthryl]-6-hydroxy-3H-xanthen-3-ones (DPAXs), which are a series of fluorescence probes for singlet oxygen that we recently developed. DMAX should be useful as a fluorescence probe for detecting (1)O(2) in a variety of biological systems.

Sequence of simian immunodeficiency virus from African green monkey, a new member of the HIV/SIV group

Some wild African green monkeys are known to be naturally infected with a retrovirus related to human immunodeficiency virus (HIV) without having any apparent symptoms of an AIDS-like disease. This simian immunodeficiency virus, designated SIVAGM, may be helpful in clarifying the evolution and pathogenicity of HIV. Some virus strains that were previously reported to be isolated from African green monkeys were shown to be laboratory contaminations of SIVMAC (SIV from a rhesus macaque) Here we report the complete DNA sequence of authentic SIVAGM, which was isolated from a naturally infected African green monkey of Kenyan origin. Comparison of the genome of SIVAGM with those of known HIV/SIVs indicates that the virus is a new simian lentivirus that is approximately equally distantly related to HIV-1 and HIV-2 in contrast to SIVMAC, which is much closer to HIV-2 than to HIV-1 (refs 5, 9).

Pharmacokinetics of soybean isoflavones in plasma, urine and feces of men after ingestion of 60 g baked soybean powder (kinako)

To take advantage of the various pharmacologic activities of soy bean isoflavones, more detailed studies of the absorption and excretion rates of these compounds in humans and subsequent evaluation of their bioavailabilities are required. We conducted a pharmacokinetic study of soybean isoflavones in seven healthy male volunteers. After ingestion of 60 g of kinako (baked soybean powder, containing 103 micromol daidzein and 112 micromol genistein), changes of the isoflavone and metabolite concentrations in plasma, urine and feces were measured by gas chromatography-mass spectrometry. The plasma concentration of genistein increased after 2 h and reached its highest value of 2.44 +/- 0.65 micromol/L 6 h later. The plasma concentration of daidzein peaked at 1.56 +/- 0.34 micromol/L at the same time, but it was always lower than that of genistein. Peak plasma concentration of O-desmethylangolensin (O-DMA) and equol appeared after the daidzein peak in four and two subjects, respectively. In contrast with plasma, daidzein was the main component in urine. Urinary daidzein excretion started to increase shortly after the rise in its plasma concentration and reached 2.4 micromol/h 8 h after ingestion of kinako. Genistein excretion in urine paralleled that of daidzein, but the value at 6 h was about half (1.1 micromol/h). The majority of ingested isoflavones after ingestion of kinako were recovered on d 2 or 3 in the feces. Total recovery of daidzein, O-DMA and equol from urine and feces was 54.7%, calculated from daidzein intake; 20.1% of administered genistein was recovered as genistein. The half-lives of plasma genistein and daidzein were 8.36 and 5.79 h, respectively. The individual plasma and urinary concentrations of equol and O-DMA were quite variable; subjects were classified as high and low metabolizers. The high plasma concentration of isoflavones for at least several hours after a single ingestion of soy protein suggests that these compounds may interact with macromolecules and have biological effects.

Local implantation of autologous bone marrow cells for therapeutic angiogenesis in patients with ischemic heart disease: clinical trial and preliminary results

A new therapy for severe ischemic heart disease has been developed; therapeutic angiogenesis induced by the local implantation of autologous bone marrow cells (BMC). After confirming that no detrimental changes were induced by this treatment in a canine heart model, a clinical trial was commenced in 1999. Thus far, 5 patients have been given this new treatment concomitant with coronary artery bypass grafting and all have been followed up for at least 1 year. Autologous BMC were implanted into the ungraftable area and postoperative cardiac scintigraphy showed specific improvement in coronary perfusion in 3 of the 5 patients. Postoperative chest radiography, electrocardiography, echocardiography and blood tests did not reveal any detrimental changes. In conclusion, this new therapy appears to be safe and could provide a treatment option for patients with otherwise untreatable ischemic heart disease.

Tissue engineering heart valves: valve leaflet replacement study in a lamb model

BACKGROUND

Valve replacements using either bioprosthetic or mechanical valves have the disadvantage that these structures are unable to grow, repair, or remodel and are both thrombogenic and susceptible to infection. These characteristics have significantly limited their durability and longevity. In an attempt to begin to overcome these shortcomings, we have tested the feasibility of constructing heart valve leaflets in lambs by seeding a synthetic polyglycolic acid fiber matrix in vitro with fibroblasts and endothelial cells.

METHODS

Mixed cell populations of endothelial cells and fibroblasts were isolated from explanted ovine arteries. Endothelial cells were selectively labeled with an acetylated low-density lipoprotein marker and separated from the fibroblasts using a fluorescent activated cell sorter. A synthetic biodegradable scaffold constructed from polyglycolic acid fibers was seeded with fibroblasts, which grew to form a tissue-like sheet. This tissue was subsequently seeded with endothelial cells, which formed a cellular monolayer coating around the leaflet. Using these constructs, autologous (n = 3) and allogenic (n = 4) tissue engineered leaflets were implanted in 7 animals. In each animal the right posterior leaflet of the pulmonary valve was resected and replaced with an engineered valve leaflet.

RESULTS

All animals survived the procedure. Postoperative echocardiography demonstrated no evidence of stenosis and trivial pulmonary regurgitation in the autografts and moderate regurgitation in the allogenic valves. Collagen analysis of the constructs showed development of an extracellular matrix. Histologic evaluation of the constructs demonstrated appropriate cellular architecture.

CONCLUSIONS

This preliminary experiment showed that a tissue engineered valve leaflet constructed from its cellular components can function in the pulmonary valve position. Tissue engineering of a heart valve leaflet is feasible, and these preliminary studies suggest that autograft tissue will probably be superior to allogenic tissue.

Effects of luteolin, quercetin and baicalein on immunoglobulin E-mediated mediator release from human cultured mast cells

BACKGROUND

Flavonoids have a variety of activities including anti-allergic activities, and are known to inhibit histamine release from human basophils and murine mast cells.

OBJECTIVE

The effects of luteolin, a flavone, on the immunoglobulin (Ig) E-mediated allergic mediator release from human cultured mast cells (HCMCs) were investigated and compared with those of baicalein and quercetin.

METHODS

HCMCs were sensitized with IgE, and then treated with flavonoids before challenge with antihuman IgE. The amount of released mediators was determined as was mobilization of intracellular Ca2+ concentration, protein kinase C (PKC) translocation and phosphorylation of intracellular proteins were detected after anti-IgE stimulation.

RESULTS

Luteolin, baicalein and quercetin inhibited the release of histamine, leukotrienes (LTs), prostaglandin D2 (PGD2), and granulocyte macrophage-colony stimulating factor (GM-CSF) from HCMC in a concentration-dependent manner. Additionally, the three flavonoids inhibited A23187-induced histamine release. As concerns Ca2+ signalling, luteolin and quercetin inhibited Ca2+ influx strongly, although baicalein did slightly. With regard to PKC signalling, luteolin and quercetin inhibited PKC translocation and PKC activity strongly, although baicalein did slightly. The suppression of Ca2+ and PKC signallings might contribute to the inhibition of mediator release. The activation of extracellular signal-regulated kinases (ERKs) and c-Jun NH2-terminal kinase (JNK), that were activated just before the release of LTs and PGD2 and GM-CSF mRNA expression in IgE-mediated signal transduction events, were clearly suppressed by luteolin and quercetin. In contrast, the flavonoids did not affect the activation of p38 mitogen-activated protein kinase (p38 MAPK) pathway.

CONCLUSION

These results indicate that luteolin is a potent inhibitor of human mast cell activation through the inhibition of Ca2+ influx and PKC activation.

Raman spectroscopic study on the copper(II) binding mode of prion octapeptide and its pH dependence

The cellular form of prion protein is a precursor of the infectious isoform, which causes fatal neurodegenerative diseases through intermolecular association. One of the characteristics of the prion protein is a high affinity for Cu(II) ions. The site of Cu(II) binding is considered to be the N-terminal region, where the octapeptide sequence PHGGGWGQ repeats 4 times in tandem. We have examined the Cu(II) binding mode of the octapeptide motif and its pH dependence by Raman and absorption spectroscopy. At neutral and basic pH, the single octapeptide PHGGGWGQ forms a 1:1 complex with Cu(II) by coordinating via the imidazole N pi atom of histidine together with two deprotonated main-chain amide nitrogens in the triglycine segment. A similar 1:1 complex is formed by each octapeptide unit in (PHGGGWGQ)2 and (PHGGGWGQ)4. Under weakly acidic conditions (pH approximately 6), however, the Cu(II)-amide- linkages are broken and the metal binding site of histidine switches from N pi to N tau to share a Cu(II) ion between two histidine residues of different peptide chains. The drastic change of the Cu(II) binding mode on going from neutral to weakly acidic conditions suggests that the micro-environmental pH in the brain cell regulates the Cu(II) affinity of the prion protein, which is supposed to undergo pH changes in the pathway from the cell surface to endosomes. The intermolecular His(N tau)-Cu(II)-His(N tau) bridge may be related to the aggregation of prion protein in the pathogenic form.

Involvement of Bruton's tyrosine kinase in FcepsilonRI-dependent mast cell degranulation and cytokine production

We investigated the role of Bruton's tyrosine kinase (Btk) in FcepsilonRI-dependent activation of mouse mast cells, using xid and btk null mutant mice. Unlike B cell development, mast cell development is apparently normal in these btk mutant mice. However, mast cells derived from these mice exhibited significant abnormalities in FcepsilonRI-dependent function. xid mice primed with anti-dinitrophenyl monoclonal IgE antibody exhibited mildly diminished early-phase and severely blunted late-phase anaphylactic reactions in response to antigen challenge in vivo. Consistent with this finding, cultured mast cells derived from the bone marrow cells of xid or btk null mice exhibited mild impairments in degranulation, and more profound defects in the production of several cytokines, upon FcepsilonRI cross-linking. Moreover, the transcriptional activities of these cytokine genes were severely reduced in FcepsilonRI-stimulated btk mutant mast cells. The specificity of these effects of btk mutations was confirmed by the improvement in the ability of btk mutant mast cells to degranulate and to secrete cytokines after the retroviral transfer of wild-type btk cDNA, but not of vector or kinase-dead btk cDNA. Retroviral transfer of Emt (= Itk/Tsk), Btk's closest relative, also partially improved the ability of btk mutant mast cells to secrete mediators. Taken together, these results demonstrate an important role for Btk in the full expression of FcepsilonRI signal transduction in mast cells.

Highly sensitive peptide-4-methylcoumaryl-7-amide substrates for blood-clotting proteases and trypsin

Seventy-four peptide amides of 7-amino-4-methylcoumarin (Mec) of the type Boc-Xaa-Yaa-Arg-NH-Mec were newly synthesized and tested to find specific substrates for blood-clotting proteases and trypsin. The Xaa and Yaa residues of these substrates have been replaced by 12 and 15 different amino acids, respectively. Among these peptides, the followings were found to be most sensitive substrates for individual enzymes: Boc-Asp(OBzl)-Pro-Arg-NH-Mec (kcat = 160 s-1, Km = 11 microM, kcat/Km = 15,000,000 M-1 s-1) for human alpha-thrombin, Z-less than Glu-Gly-Arg-NH-Mec (kcat = 19 s-1, Km = 59 microM, kcat/Km = 320,000 M-1 s-1) for bovine factor Xa, Boc-Gln-Gly-Arg-NH-Mec (kcat = 5.8 s-1, Km = 140 microM, kcat/Km = 42,000) for bovine factor XIIa, Boc-Asp(OBzl)-Ala-Arg-NH-Mec (kcat = 9.2 s-1, Km = 120 microM, kcat/Km = 77,000 M-1 s-1) for bovine activated protein C, and Boc-Gly-Phe-Arg-NH-Mec (kcat = 29 s-1, Km = 230 microM, kcat/Km = 130,000 M-1 s-1) for bovine plasma kallikrein. Moreover, Boc-Glu(OBzl)-Ala-Arg-NH-Mec (kcat = 46 s-1, Km = 370 microM, kcat/Km = 120,000 M-1 s-1) was newly found as a good substrate for human factor XIa. Bovine trypsin effectively hydrolyzed peptide-NH-Mec substrates containing Ala and Pro at the P2 site. The most reactive substrate was Boc-Gln-Ala-Arg-NH-Mec (kcat = 120 s-1, Km = 6.0 microM, kcat/Km = 20,000,000 M-1 s-1).

Protonation of histidine and histidine-tryptophan interaction in the activation of the M2 ion channel from influenza a virus

The M2 protein of influenza A virus forms a homotetramer ion channel in the lipid membrane. The channel is specific for proton conductance and is activated by low pH with a transition midpoint at pH 5.7. We have studied the structure of the transmembrane domain of the M2 ion channel by using UV resonance Raman spectroscopy, with special attention to the side chains of histidine (His37) and tryptophan (Trp41) residues. The Raman spectra provide direct evidence that the imidazole ring of His37 is protonated upon channel activation at low pH. Concomitantly, the UV resonance Raman scattering from Trp41 shows an unusual intensity change, which is ascribed to a cation-pi interaction between the protonated (cationic) imidazole ring of His37 and the indole ring of Trp41. The protonation of His37 and the Raman intensity change of Trp41 do not occur in the presence of amantadine that blocks the M2 ion channel. These observations clearly show that the protonation of His37 and concomitant cation-pi interaction with Trp41 is a key step in the activation of the M2 ion channel. The His37-Trp41 interaction associated with the channel activation is explained by assuming a conformational transition of His37 induced by electrostatic repulsion among the protonated imidazole rings of four His37 residues in the tetramer channel. Trp41 may play a role in stabilizing the channel open state through cation-pi interaction with His37. A molecular model for the activation of M2 ion channel is proposed on the basis of the gating mechanism.

Estradiol-17beta stimulates the renewal of spermatogonial stem cells in males

In this work, we examined the functions of the female hormone "estrogen" on spermatogenesis of the Japanese eel (Anguilla japonica). Estradiol-17beta (E(2)), a natural estrogen in vertebrates, was present in the serum and its receptor was expressed in the testis during the whole process of spermatogenesis. Spermatogonial stem cell renewal was promoted by E(2) implantation but was suppressed by tamoxifen (an antagonist of estrogen). In vitro, 10 pg/ml of E(2) was sufficient to induce spermatogonial stem cell division in cultured testicular tissue, therefore confirming the in vivo observations. These results clearly show that estrogen is an indispensable "male hormone" in the early spermatogenetic cycle.

Characterization of individual tryptophan side chains in proteins using Raman spectroscopy and hydrogen-deuterium exchange kinetics

Two Raman bands at 880 and 1360 cm-1 of tryptophan (Trp) side chains have been found useful in structural studies of the side chains in proteins. The frequency of the 880-cm-1 band reflects the strength of H bonding at the N1H site of the indole ring: the lower the frequency is, the stronger the H bonding is. The intensity of the 1360-cm-1 band, on the other hand, is a marker of the hydrophobicity of the environment of the indole ring: particularly strong in hydrophobic environments. It is also demonstrated that a combination of stepwise deuteration of the tryptophan side chains and difference spectrum techniques is useful to observe these marker bands due to each side chain separately. The states of six tryptophans in lysozyme revealed by this Raman spectroscopic method in solution are compared with those by X-ray diffraction in crystal. The Raman data on the outer four Trp's are consistent with the X-ray structure, whereas significant differences between solution and crystal are suggested for the strength of H bonding of the most and second most buried Trp's. Characterization of four Trp's in alpha-lactalbumin shows that the two outer Trp's are moderately H bonded to solvent water and closely surrounded by aliphatic side chains while the inner two are not H bonded nor closely surrounded by aliphatic side chains.

The role of hormones in the acquisition of sperm motility in salmonid fish

In salmonid fish, spermatozoa taken from the testes are immotile, but acquire motility during their passage through the sperm duct. Using male masu salmon (Oncorhynchus masou), we found that gonadotropin-induced testicular production of 17 alpha, 20 beta-dihydroxy-4-pregnen-3-one (17 alpha, 20 beta-DP), the oocyte maturation-inducing hormone of salmonid fish, is responsible for the acquisition of sperm motility. However, neither testosterone (T) nor 11-ketotestosterone (11-KT), the two major androgens in teleost fish, were effective. We also present evidence that 17 alpha, 20 beta-DP action is mediated through an increase in sperm duct pH, which in turn increases the cAMP content of sperm allowing the acquisition of motility.

Effects of Sho-saiko-to, a Japanese herbal medicine, on hepatic fibrosis in rats

It has been shown that lipid peroxidation is associated with hepatic fibrosis and stellate cell activation. Sho-saiko-to (TJ-9) is an herbal medicine, which is commonly used to treat chronic hepatitis in Japan, although the mechanism by which TJ-9 protects against hepatic fibrosis is not known. As a result, we assayed the preventive and therapeutic effects of TJ-9 on experimental hepatic fibrosis, induced in rats by dimethylnitrosamine (DMN) or pig serum (PS), and on rat stellate cells and hepatocytes in primary culture, and assessed the antioxidative activities and the active components of TJ-9. Male Wistar rats were given a single intraperitoneal injection of 40 mg/kg DMN or 0.5 mL PS twice weekly for 10 weeks. In each model, rats were fed a basal diet throughout, or the same diet, which also contained 1.5% TJ-9, for 2 weeks before treatment or for the last 2 weeks of treatment. TJ-9 suppressed the induction of hepatic fibrosis, increased hepatic retinoids, and reduced the hepatic levels of collagen and malondialdehyde (MDA), a production of lipid peroxidation. Immunohistochemical examination showed that TJ-9 reduced the deposition of type I collagen and the number of alpha-smooth muscle actin (alpha-SMA) positive-stellate cells in the liver and inhibited, not only lipid peroxidation in cultured rat hepatocytes that were undergoing oxidative stress, but also the production of type I collagen, alpha-SMA expression, cell proliferation, and oxidative burst in cultured rat stellate cells. In addition, TJ-9 inhibited Fe2+/adenosine 5'-diphosphate-induced lipid peroxidation in rat liver mitochondria in a dose-dependent manner and showed radical scavenging activity. Among the active components of TJ-9, baicalin and baicalein were found to be mainly responsible for the antioxidative activity. These findings suggest that Sho-saiko-to (TJ-9) functions as a potent antifibrosuppressant by inhibition of lipid peroxidation in hepatocytes and stellate cells in vivo.

An essential role of mast cells in the development of airway hyperresponsiveness in a murine asthma model

Immunization of BALB/c mice with alum-adsorbed OVA, followed by three bronchoprovocations with aerosolized OVA, resulted in the development of airway hyperresponsiveness (AHR) and allergic inflammation in the lung accompanied by severe infiltration of eosinophils into airways. In this murine asthma model, administration of monoclonal anti-IL-5 Ab before each Ag challenge markedly inhibited airway eosinophilia, but the treatment did not affect the development of AHR. Immunization and aerosol challenges with OVA following the same protocol failed to induce AHR in the mast cell-deficient W/Wv mice, but induced AHR in their congenic littermates, i.e., WBB6F1 (+/+) mice. No significant difference was found between the W/Wv mice and +/+ mice with respect to the IgE and IgG1 anti-OVA Ab responses and to the airway eosinophilia after Ag provocations. It was also found that reconstitution of W/Wv mice with bone marrow-derived mast cells cultured from normal littermates restored the capacity of developing Ag-induced AHR, indicating that lack of mast cells was responsible for the failure of W/Wv mice to develop Ag-induced AHR under the experimental conditions. However, the OVA-immunized W/Wv mice developed AHR by increasing the frequency and Ag dose of bronchoprovocations. The results suggested that AHR could be developed by two distinct cellular mechanisms. One would go through mast cell activation and the other is IgE/mast cell independent but an eosinophil/IL-5-dependent mechanism.

Stereospecific reduction of phosphine oxides to phosphines by the use of a methylation reagent and lithium aluminum hydride

[figure: see text] Various phosphine oxides are efficiently reduced by the use of a methylation reagent and lithium aluminum hydride. Optically active P-chirogenic phosphine oxides are also reduced with inversion of configuration at phosphorus atom by treatment with methyl triflate, followed by reaction with LiAlH4.

Hypoxic induction of prolyl 4-hydroxylase alpha (I) in cultured cells

Accumulated evidence indicates that hypoxia activates collagen synthesis in tissues. To explore the molecular mechanism of activation, we screened genes that are up-regulated or down-regulated by hypoxia. Fibroblasts isolated from fetal rat lung were cultured under hypoxia. Differential display technique showed that the mRNA level of prolyl 4-hydroxylase (PH) alpha(I), an active subunit that catalyzes the oxygen-dependent hydroxylation of proline residue in procollagen, increased 2-3-fold after an 8-h exposure to hypoxia. This elevated level was maintained over 40 h and returned to the basal level after reoxygenation. The transcription rate, protein level, and hydroxyproline content (an indicator of the prolyl hydroxylation) were all elevated by hypoxic culture. Analysis of the promotor region of PHalpha(I) gene indicated that a motif similar to hypoxia-responsive element (HRE) of hypoxia-inducible genes such as erythropoietin, was identified within a 120-base pair sequence upstream of the transcription start site. Luciferase reporter assay and mutational analysis showed that a site similar to the HRE in this motif is functionally essential to hypoxic response. Electrophoretic mobility shift assay revealed that hypoxia-inducible factor-1 was stimulated and bound to the PHalpha(I) HRE upon hypoxic challenge. Our results indicate that PHalpha(I), an essential enzyme for collagen synthesis, is a target gene for hypoxia-inducible factor-1.

Isolation and characterization of simian immunodeficiency virus from mandrills in Africa and its relationship to other human and simian immunodeficiency viruses

Two isolates of simian retrovirus related to the human immunodeficiency virus (HIV) were obtained from apparently healthy mandrills, Papio (Mandrillus) sphinx, in western equatorial Africa. This virus, designated SIVMND (simian immunodeficiency virus from mandrills), appeared morphologically similar to HIV by electron microscopy, showed Mg2+-dependent reverse transcriptase activity, and induced cytopathic effect in human CD4-positive cells. Western blotting (immunoblotting) analyses revealed that the gag and pol products of SIVMND showed cross-reactivity with those of known HIVs and SIVs. Molecular clones covering full-length viral DNA were obtained from closed circular extrachromosomal DNA of SIVMND-infected cells. By clone-on-clone hybridization with known retroviruses of the HIV and SIV groups, SIVMND showed similar cross-hybridization with HIV-1, HIV-2, SIVAGM (African green monkey-derived SIV), and SIVMAC (rhesus macaque-derived SIV) in the gag and pol regions only at low stringency but not at high stringency, a result indicating that SIVMND is a new member of the HIV-SIV group. The existence of distinct SIVs in different monkey species suggest that recent interspecies transfer of HIV-SIV is unlikely in nature.

Phylogenetic subtypes of human T-lymphotropic virus type I and their relations to the anthropological background

Isolates of human T-lymphotropic virus type I (HTLV-I) were phylogenetically analyzed from native inhabitants in India and South America (Colombia and Chile) and from Ainu (regarded as pure Japanese descendants from the preagricultural "Jomon" period). Their genomes were partially sequenced together with isolates from Gabon in central Africa and from Ghana in West Africa. The phylogenetic tree was constructed from the sequence data obtained and those of previously reported HTLV-I isolates and simian T-lymphotropic virus type I (STLV-I) isolates. The heterogeneity of HTLV-I was recently recognized, and one major type, generally called the "cosmopolitan" type, contained Japanese, Caribbean, and West African isolates. The phylogenetic tree constructed in the present study has shown that this cosmopolitan type can be further grouped into three lineages (subtypes A, B, and C). Subtype A consists of some Caribbean, two South American, and some Japanese isolates, including that from the Ainu, in addition to an Indian isolate, and subtype B consists of other Japanese isolates in addition to another Indian isolate, suggesting that there might be at least two ancestral lineages of the Japanese HTLV-I. Subtype A implies a close connection of the Caribbean and South American natives with the Japanese and thereby a possible migration of the lineage to the American continent via Beringia in the Paleolithic era. Subtype C consists of the West African and other Caribbean isolates, indicating that not all but part of the Caribbean strains directly originated from West Africa probably during the period of slave trade. The tree also has shown that the HTLV-I isolate from Gabon in central Africa forms a cluster with STLV-I from a chimpanzee, suggesting a possible interspecies transmission between man and the chimpanzee in the past. No specific clustering was observed in the tree in relation to manifestations of the disease such as adult T-cell leukemia and HTLV-I-related neurological disorders. Thus, the topology of the phylogenetic tree reflects the movement of people carrying the virus in the past.

Involvement of sex steroid hormones in the early stages of spermatogenesis in Japanese huchen (Hucho perryi )

In higher vertebrates, considerable progress has been made in understanding the endocrine regulation of puberty; however, in teleosts, the regulatory mechanisms of spermatogenesis during the first annual cycle remain unclear. The present study was conducted to understand the regulatory mechanisms of spermatogenesis throughout the different stages of the first spermatogenic cycle and to check the ability of various steroids and hormones to induce in vitro spermatogonial proliferation in Japanese huchen (Hucho perryi ). The results indicate that the serum level of 11-ketotestosterone (11-KT) was positively associated with germ cell type; the level first began to rise with the appearance of late-type B spermatogonia and continued to increase gradually throughout the active spermatogenic stages and spermiogenesis, reaching a peak value 2 wk before spawning, and then declined. During the spermatogenic stages, the serum concentration of 17alpha,20beta-dihydroxy-4-pregnen-3-one (17alpha,20beta-DP) was undetectable. Only a small peak was detected with the appearance of spermatocytes and spermatids, and at the time of spawning, the level increased dramatically, reaching its maximum value with the onset of milt production. Despite the high variation in serum levels of 17beta-estradiol (E2) both between months and among the individuals, E2 was found during the whole reproductive cycle. From these results, we concluded that 1) 11-KT is necessary for the initiation of spermatogenesis and sperm production, and it probably plays a role in spermiation, 2) 17alpha,20beta-DP is essential for the final maturation stage, could play a significant role in the mitosis phase and meiosis process, and probably participates in the regulation of spawning behavior, and 3) estrogen is an indispensable male hormone that plays a physiological role in some aspects of testicular functions, especially during the mitotic phase. The three steroids were also able to induce DNA synthesis, spermatogonial renewal, and/or spermatogonial proliferation in vitro.

Higher hematocrit improves cerebral outcome after deep hypothermic circulatory arrest

BACKGROUND

Various degrees of hemodilution are currently in clinical use during deep hypothermic circulatory arrest to counteract deleterious rheologic effects linked with brain injury by previous reports.

MATERIAL AND METHODS

Seventeen piglets were randomly assigned to three groups. Group I piglets (n = 7) received colloid and crystalloid prime (hematocrit < 10%), group II piglets (n = 5) received blood and crystalloid prime (hematocrit 20%), group III piglets (n = 5) received blood prime (hematocrit 30%). All groups underwent 60 minutes of deep hypothermic circulatory arrest at 15 degrees C with continuous magnetic resonance spectroscopy and near-infrared spectroscopy Neurologic recovery was evaluated for 4 days (neurologic deficit score 0, normal, to 500, brain death; overall performance category 1, normal, to 5, brain death). Neurohistologic score (0, normal, to 5+, necrosis) was assessed after the animals were euthanized on day 4.

RESULTS

Group I had significant loss of phosphocreatine and intracellular acidosis during early cooling (phosphocreatine in group I, 86.3% +/- 26.8%; group II, 117.3% +/- 8.6%; group III, 110.9% +/- 2.68%; p = 0.0008; intracellular pH in group I, 6.95 +/- 0.18; group II, 7.28 +/- 0.04; group III, 7.49 +/- 0.04; p = 0.0048). Final recovery was the same for all groups. Cytochrome aa3 was more reduced in group I during deep hypothermic circulatory arrest than in either of the other groups (group I, -43.6 +/- 2.6; group II, -16.0 +/- 5.2; group III, 1.3 +/= 3.1; p < 0.0001). Neurologic deficit score was best preserved in group III (p < 0.05 group II vs group III) on the first postoperative day, although this difference diminished with time and all animals were neurologically normal after 4 days. Histologic assessment was worst among group I in neocortex area (group I, 1.33 +/- 0.3; group II, 0.22 +/- 0.1; group III, 0.40 +/- 0.2, p < 0.05, group I vs group II; p = 0.0287, group I vs group III).

CONCLUSION

Extreme hemodilution during cardiopulmonary bypass may cause inadequate oxygen delivery during early cooling. The higher hematocrit with a blood prime is associated with improved cerebral recovery after deep hypothermic circulatory arrest.