The effects of ketamine and propofol on neuronal nicotinic acetylcholine receptors and P2x purinoceptors in PC12 cells

We studied the effects of ketamine and propofol on two ligand-gated ion channels mediating fast synaptic transmission through sympathetic ganglia, neuronal nicotinic acetylcholine receptors (nAchRs), and P2X purinoceptors in a rat pheochromocytoma cell line PC12 using whole cell voltage clamp recording. Ketamine and propofol similarly inhibited the nicotine-induced inward current reversibly and dose-dependently at the membrane potential of -60 mV but had no effects on the adenosine triphosphate-induced current. Both anesthetics accelerated the current decay during agonist application, resulting in greater inhibition on the steady current than the peak current. The 50% inhibition concentration values for the steady current were lower than the clinically relevant concentrations for ketamine (2.8+/-0.6 microM) and higher than those for propofol (5.4+/-0.6 microM). Both anesthetics induced an addition of the fast component to the decay phase and an acceleration of the slow component, which suggests an open channel blockade or an enhancement of desensitization as a mechanism. The effects on closed channels seemed to be small because preincubation with the anesthetics did not significantly augment the block. Inhibition was voltage-independent at membrane potentials between -20 and -70 mV and was consistent with a noncompetitive block. Inhibition of the neuronal nAchR-mediated current may lead to the suppression of synaptic transmission in sympathetic ganglia by ketamine, but not by propofol, at the clinically relevant concentrations. However, these results are not consistent with changes in sympathetic nerve activities reported for animals or humans anesthetized with ketamine or propofol, which suggests effects from other systems, such as the central nervous system in vivo.

IMPLICATIONS

Ketamine (at smaller than clinically relevant concentrations) and propofol (at larger than clinically relevant concentrations) inhibited neuronal nicotinic acetylcholine receptor-mediated current in PC12 cells, which possess the receptors that resemble those in postganglionic sympathetic neurons. These findings are not consistent with in vivo experiments, which suggests that effects from other systems, such as the central nervous system, are of importance.

The first step of gibberellin biosynthesis in pumpkin is catalyzed by at least two copalyl diphosphate synthases encoded by differentially regulated genes

The first step in gibberellin biosynthesis is catalyzed by copalyl diphosphate synthase (CPS) and ent-kaurene synthase. We have cloned from pumpkin (Cucurbita maxima L.) two cDNAs, CmCPS1 and CmCPS2, that each encode a CPS. Both recombinant fusion CmCPS proteins were active in vitro. CPS are translocated into plastids and processed by cleavage of transit peptides. For CmCPS1 and CmCPS2, the putative transit peptides cannot exceed the first 99 and 107 amino acids, respectively, because longer N-terminal deletions abolished activity. Levels of both CmCPS transcripts were strictly regulated in an organ-specific and developmental manner. Both transcripts were almost undetectable in leaves and were abundant in petioles. CmCPS1 transcript levels were high in young cotyledons and low in roots. In contrast, CmCPS2 transcripts were undetectable in cotyledons but present at significant levels in roots. In hypocotyls, apices, and petioles, CmCPS1 transcript levels decreased with age much more rapidly than those of CmCPS2. We speculate that CmCPS1 expression is correlated with the early stages of organ development, whereas CmCPS2 expression is correlated with subsequent growth. In contrast, C. maxima ent-kaurene synthase transcripts were detected in every organ at almost constant levels. Thus, ent-kaurene biosynthesis may be regulated through control of CPS expression.

Phytochrome regulates gibberellin biosynthesis during germination of photoblastic lettuce seeds

Germination of lettuce (Lactuca sativa L.) seed is regulated by phytochrome. The requirement for red light is circumvented by the application of gibberellin (GA). We have previously shown that the endogenous content of GA1, the main bioactive GA in lettuce seeds, increases after red-light treatment. To clarify which step of GA1 synthesis is regulated by phytochrome, cDNAs encoding GA 20-oxidases (Ls20ox1 and Ls20ox2, for L. sativa GA 20-oxidase) and 3beta-hydroxylases (Ls3h1 and Ls3h2 for L. sativa GA 3beta-hydroxylase) were isolated from lettuce seeds by reverse-transcription polymerase chain reaction. Functional analysis of recombinant proteins expressed in Escherichia coli confirmed that the Ls20ox and Ls3h encode GA 20-oxidases and 3beta-hydroxylases, respectively. Northern-blot analysis showed that Ls3h1 expression was dramatically induced by red-light treatment within 2 h, and that this effect was canceled by a subsequent far-red-light treatment. Ls3h2 mRNA was not detected in seeds that had been allowed to imbibe under any light conditions. Expression of the two Ls20ox genes was induced by initial imbibition alone in the dark. The level of Ls20ox2 mRNA decreased after the red-light treatment, whereas that of Ls20ox1 was unaffected by light. These results suggest that red light promotes GA1 synthesis in lettuce seeds by inducing Ls3h1 expression via phytochrome action.

[Current status of acute respiratory infections in children under five years of age in Nairobi, Kenya]

Two hundreds and twenty-six children under five years of age with pneumonia were recruited from an urban poor area in Nairobi, Kenya, and examined for pathogens for 1 year from February 1997. One hundred and twenty-eight of the 226 patients were pathogen-positive cases. The patients under 1-year-old were 61.8% of the pathogen-positive cases. A total 192 organisms were isolated from 128 pathogen-positive patients. Streptococcus pneumoniae had the highest prevalence rate of 31.3%, followed by respiratory syncytial virus with 10.4%, Candida albicans with 9.9%, Moraxella (B) catarrhalis with 7.8%. In S. pneumoniae, 66.7% of the organism was resistant to oxacillin. It was also shown that 51.1% and 65.1% of the S. pneumoniae strains were resistant to gentamicin and trimethoprim/sulfam, respectively. From these results, it is clear that a lot of multi-drug resistant S. pneumoniae strains including penicillin-resistant S. pneumoniae were frequently detected in an urban poor area.

Phytochrome regulation and differential expression of gibberellin 3beta-hydroxylase genes in germinating Arabidopsis seeds

Despite extensive studies on the roles of phytochrome in photostimulated seed germination, the mechanisms downstream of the photoreceptor that promote germination are largely unknown. Previous studies have indicated that light-induced germination of Arabidopsis seeds is mediated by the hormone gibberellin (GA). Using RNA gel blot analyses, we studied the regulation of two Arabidopsis genes, GA4 and GA4H (for GA4 homolog), both of which encode GA 3beta-hydroxylases that catalyze the final biosynthetic step to produce bioactive GAs. The newly isolated GA4H gene was expressed predominantly during seed germination. We show that expression of both GA4 and GA4H genes in imbibed seeds was induced within 1 hr after a brief red (R) light treatment. In the phytochrome B-deficient phyB-1 mutant, GA4H expression was not induced by R light, but GA4 expression still was, indicating that R light-induced GA4 and GA4H expression is mediated by different phytochromes. In contrast to the GA4 gene, the GA4H gene was not regulated by the feedback inhibition mechanism in germinating seeds. Our data demonstrate that expression of GA 3beta-hydroxylase genes is elevated by R light, which may result in an increase in biosynthesis of active GAs to promote seed germination. Furthermore, our results suggest that each GA 3beta-hydroxylase gene plays a unique physiological role during light-induced seed germination.

Molecular cloning of a novel sex pheromone responsible for the release of a different sex pheromone in Closterium peracerosum-strigosum-littorale complex

A sex pheromone, protoplast-release-inducing protein (PR-IP) inducer, of the Closterium peracerosum-strigosum-littorale complex is known to induce the release of PR-IP, from mating-type plus (mt+) cells during sexual reproduction. The purified PR-IP inducer was treated with trypsin to obtain internal peptides for determination of partial amino acid sequences. Using these sequences, oligonucleotides were synthesized and used as primers for the combined reverse transcription-PCR. A 296 bp cDNA fragment was amplified, permitting the cloning of corresponding full length cDNA (CpPI; Closterium peracerosum-strigosum-littorale complex PR-IP inducer). The deduced amino acid sequence of CpPI encodes a protein of 212 amino acid residues of M(r) 23,071 whereas portion of the peptide secreted is predicted to have 142 amino acid residues of M(r) 15,717 and shows no significant similarity with known proteins. The predicted protein has three possible consensus sequences for asparagine-linked glycosylation site. The CpPI gene was expressed when mating-type minus (mt-) cells were incubated at a low cell density in the light. Nitrogen deprivation from the medium enhances expression of the CpPI gene. An analysis by genomic Southern hybridization revealed that the cDNA probe hybridized to several DNA fragments obtained from both the genome of mt- and mt+ cells. However, in mt- cells, transcripts for the PR-IP inducer could not be detected by Northern hybridization.

Inhibition of the neuronal nicotinic receptor-mediated current by kappa opioid receptor agonists in PC12 cells

The authors studied effects of opioid receptor agonists on neuronal nicotinic-receptor-mediated current in PC12 cells using whole-cell current recording. At 1 microM, [d-Ala, N-Me, Phe, Gly-ol]- enkephalin (DAMGO), a selective micro receptor agonist, or 10 microM methionine-enkephalin, a micro and delta receptor agonist, did not inhibit the current elicited by 30 microM nicotine significantly. Dynorphin A (1-17) (0.1-1 microM), an endogenous kappa receptor agonist, and U50488 (0.1-10 microM), a non-peptide selective kappa receptor agonist, depressed the nicotine-induced current reversibly in a dose-dependent manner. They accelerated the current decay, resulting in greater effects on the non-desensitized current than the peak current. These effects were not affected by nor-binaltrophimine, a selective kappa receptor antagonist, or by inclusion of guanosine 5'-O-(2-thiobiphosphate) (GDP[beta-S]), a GTP binding protein blocker, into the pipette solution. These results demonstrate that two kappa opioid receptor agonists, dynorphin A (1-17) and U50488, inhibit neuronal nicotinic-receptor-mediated current without the involvement of opioid receptors or GTP binding proteins. The acceleration of the current decay suggests a direct action on nicotinic receptors such as open channel block, or augmentation of desensitization. Modulation of neuronal nicotinic receptors by dynorphins may play a role in some areas where dynorphin release sites and neuronal nicotinic receptors are colocalized.

S-adenosyl-L-methionine:L-methionine S-methyltransferase from germinating barley. Purification and localization

S-Adenosyl-L-methionine:L-methionine S-methyltransferase (MMT) catalyzes the synthesis of S-methyl-L-methionine (SMM) from L-methionine and S-adenosyl-L-methionine. SMM content increases during barley (Hordeum vulgare L.) germination. Elucidating the role of this compound is important from both a fundamental and a technological standpoint, because SMM is the precursor of dimethylsulfide, a biogenic source of atmospheric S and an undesired component in beer. We present a simple purification scheme for the MMT from barley consisting of 10% to 25% polyethylene glycol fractionation, anion-exchange chromatography on diethylaminoethyl-Sepharose, and affinity chromatography on adenosine-agarose. A final activity yield of 23% and a 2765-fold purification factor were obtained. After digestion of the protein with protease, the amino acid sequence of a major peptide was determined and used to produce a synthetic peptide. A polyclonal antibody was raised against this synthetic peptide conjugated to activated keyhole limpet hemocyanin. The antibody recognized the 115-kD denatured MMT protein and native MMT. During barley germination, both the specific activity and the amount of MMT protein increased. MMT-specific activity was found to be higher in the root and shoot than in the endosperm. MMT could be localized by an immunohistochemical approach in the shoot, scutellum, and aleurone cells but not in the root or endosperm (including aleurone).

Atypical Takayasu arteritis: late onset and arthritic manifestations: report of two cases

We recently experienced two cases of Takayasu arteritis rendered atypical by late onset (over 60 years of age) of disease, involvement of distal branch arteries, and association with rheumatoid arthritis. In both cases, roentgenologic examination revealed typical appearance of the abdominal aorta and stenosis of the subclavian artery entirely compatible with Takayasu arteritis. In addition, Case 1 had occlusive lesions of the superficial femoral arteries and Case 2 manifested occlusion of the axillary artery. Laboratory findings showed increased ESR and CRP but negative HLA B52 locus. Both cases showed arthritis symptoms with swelling, pain, and tenderness in joints. Case 1 did not manifest erosive lesions and positive RA test; Case 2 showed roentgenologic erosive lesions in hand joints with positive RA test. A surgical specimen from the femoral artery of Case 1 showed lesions suggesting Takayasu arteritis. Based upon these findings, we diagnosed the two patients as having atypical Takayasu arteritis with late middle age onset and arthritic manifestations.

Pregnant woman with transient diabetes insipidus resistant to 1-desamino-8-D-arginine vasopressin

We encountered a pregnant woman with transient diabetes insipidus which developed during the third trimester. A hypertonic saline infusion study did not concentrate the osmolality of urine. Her laboratory data showed hypokalemia, hyperreninemia, an increased concentration of plasma aldosterone and an increased urinary excretion rate of prostaglandin E2, which resembled hyperprostaglandin E-syndrome. T1-weighted magnetic resonance imaging of the posterior pituitary gland revealed decreased intensity. Polyuria reached 4-6 L daily, and urine osmolality remained dilute despite a lapse of four days since treatment with intranasal 1-desamino-8-D-arginine vasopressin (dDAVP: 10-25 microg every 12 h). The patient was conservatively managed without medical treatment, then delivered in the 38th week of pregnancy without complication. The osmolality of the patient's urine was higher than that of the plasma when tested 3 days postpartum. The abnormality of magnetic resonance imaging of the posterior pituitary gland disappeared at 6 months after delivery. We consider that subclinical nephrogenic diabetes insipidus in our patient was exacerbated during pregnancy.

Gibberellin biosynthesis in Gibberella fujikuroi: cloning and characterization of the copalyl diphosphate synthase gene

The gene coding for copalyl diphosphate synthase (CPS), which represents the first gene of the gibberellin pathway, was isolated from the rice pathogen Gibberella fujikuroi. This fungus is used commercially for the production of gibberellic acid and related gibberellins. CPS is a terpene cyclase which catalyzes the first specific step of the gibberellin (GA) pathway as it branches off from the general isoprenoid (biosynthetic) pathway at geranylgeranyl disphosphate (GGDP). A cDNA fragment of the cps gene from the fungus G. fujikuroi was amplified by RT-PCR using oligonucleotides based on amino-acid sequences which were conserved between the plant CPSs and the bifunctional CPS/KS of the fungus Phaeosphaeria sp. L487. A 588-bp fragment obtained with nested PCR was used to isolate the corresponding genomic clone of the cps gene from the wild-type lambda-library. This gene consists of three exons and two introns. The three exons are 2877 bp long and encode 959 amino-acid residues. The protein shares 48% identity with the bifunctional Phaeosphaeria sp. L487 FCPS and between 16% and 18% identity to the corresponding plant CPSs. Expression of the G. fujikuroi cps gene is strongly enhanced under conditions optimized for gibberellin biosynthesis and is reduced when high amounts of ammonium are present in the medium. Gene disruption, followed by gibberellin assays and Southern-blot analysis of the transformants, demonstrated clearly that the cloned gene has the expected function in the biosynthesis of fungal gibberellins.

Surgical successful treatment of Cushing's syndrome in a pregnant patient complicated with severe cardiac involvement

We encountered a case of a pregnant woman with adrenal causes of Cushing's syndrome who exhibited congestive heart failure as an initial symptom. Since the patient was also a diabetic, we treated her with high levels of diuretics and insulin. Echocardiography revealed a remarkable thickening of the left ventricle without asymmetric hypertrophy. The diagnosis of Cushing's syndrome caused by adrenal adenoma was confirmed by the endocrinological data and magnetic resonance imaging. The right adrenal adenoma was removed in the 28th week of pregnancy. After the operation, her congestive heart failure and hyperglycemia dramatically improved. Five weeks after the operation, she delivered a normal infant by caesarean section without complications. Only 4 months after delivery, the thickening of her left ventricle was normalized. We consider that the progression of her left ventricular hypertrophy induced by the changes in hemodynamic load during pregnancy may have been augmented by the excess of plasma cortisol. Operative therapy may be recommended for pregnant Cushing's syndrome patients with severe hypercortisolism complicating congestive heart failure.

Gibberellin dose-response regulation of GA4 gene transcript levels in Arabidopsis

The gibberellins (GAs) are a complex family of diterpenoid compounds, some of which are potent endogenous regulators of plant growth. As part of a feedback control of endogenous GA levels, active GAs negatively regulate the abundance of mRNA transcripts encoding GA biosynthesis enzymes. For example, Arabidopsis GA4 gene transcripts encode GA 3beta-hydroxylase, an enzyme that catalyzes the conversion of inactive to active GAs. Here we show that active GAs regulate GA4 transcript abundance in a dose-dependent manner, and that down-regulation of GA4 transcript abundance is effected by GA4 (the product of 3beta-hydroxylation) but not by its immediate precursor GA9 (the substrate). Comparison of several different GA structures showed that GAs active in promoting hypocotyl elongation were also active in regulating GA4 transcript abundance, suggesting that similar GA:receptor and subsequent signal transduction processes control these two responses. It is interesting that these activities were not restricted to 3beta-hydroxylated GAs, being also exhibited by structures that were not 3beta-hydroxylated but that had another electronegative group at C-3. We also show that GA-mediated control of GA4 transcript abundance is disrupted in the GA-response mutants gai and spy-5. These observations define a sensitive homeostatic mechanism whereby plants may regulate their endogenous GA levels.

Characterization of an Arabidopsis thaliana mutant that has a defect in ABA accumulation: ABA-dependent and ABA-independent accumulation of free amino acids during dehydration

In an attempt to elucidate the physiological role of ABA in seed dormancy and the adaptive response to dehydration, we isolated an ABA-deficient mutant of Arabidopsis thaliana (L.) Heynh. which germinated in the presence of a gibberellin biosynthetic inhibitor. Genetic analysis showed this mutation is a new allele of a recently reported locus aba2, and therefore has been designated aba2-2. The levels of endogenous ABA in fresh and dehydrated tissues of the aba2-2 mutant were highly reduced compared to those of wild-type plants. As a consequence, aba2-2 plants wilt and produce seeds with reduced dormancy. Dark germinated seedlings of the aba2-2 mutant showed true leaves, which were not observed in those of the wild type, indicating that aba2-2 embryos grew precociously during seed maturation. In the dehydrated tissues of the wild-type plants, the levels of free proline, isoleucine and leucine were elevated to a content approximately 100-fold higher than those in fresh tissues. In contrast to the wild-type plants, dehydration-induced accumulation of proline was highly suppressed in the aba2-2 mutant plants while that of leucine and isoleucine accumulated. Furthermore, exogenous application of ABA to wild-type plants promoted accumulation of free proline, but not leucine nor isoleucine. These results suggest that dehydration-induced accumulation of free leucine and isoleucine is achieved independent of ABA.

[Outcomes of 50 leukemia patients who received bone marrow transplants from unrelated donors]

Fifty leukemia patients were given bone marrow transplants (BMTs) from unrelated donors at Meitetsu Hospital. We studied the outcomes of their transplants from two perspectives: leukemia disease stage and acute graft versus host disease (GVHD). The probability of disease-free survival for standard-risk, high-risk, and super-high risk patients was 65%, 29%, and 8%, respectively. The main causes of death were septicemia, cardiac and renal failure, and relapse of leukemia in the high- and super-high risk patients, and grade III-IV acute GVHD in the standard-risk patients. The incidence of grade II-IV and grade III-IV acute GVHD was 32% and 17%, respectively. All 7 patients in whom grade III-IV severe acute GVHD developed died. We conclude that better control of acute GVHD and treatment of early stage complications are clearly important to improving the outcome of BMTs from unrelated donors, especially for high and super-high risk patients.

[Rapid tapering of cyclosporine for cytogenetic relapse shortly after bone marrow transplantation in a patient with chronic myeloid leukemia]

A 53-year-old female case of cytogenetically relapsed chronic myeloid leukemia after allogeneic bone marrow transplantation (BMT) who achieved remission by withdrawal of immunosuppressant is reported. On day 690 of this presentation she is well and alive with performance status of 100%. She had episodes of cyclic oscillation of her neutrophil count during hydroxyurea therapy lasting 1 year before transplantation. Increase of the neutrophils at the time of BMT might have contributed to her early relapse on day 207. Withdrawal of immunosuppressant was successful at least in this case.

Installation of new damped cavities at the Photon Factory storage ring

New damped cavities have been installed in the Photon Factory (PF) storage ring and successfully operated in the last scheduled user run of 1996. The new damped cavity is a simple single-cell cavity with somewhat large beam-duct holes. The part of the beam duct that is attached to the cavity is made of SiC, which works as a microwave absorber and damps the higher-order modes excited in the cavity. Because of its simple structure, the operation of the cavity is very stable and also a high power input of more than 150 kW is possible. No coupled-bunch instabilities due to the new cavity were observed during operation.

Strong synergistic anti-peroxidative effects of HDL3 and ascorbic acid against copper-catalyzed LDL peroxidation

The aim of this study was to investigate the effects of high density lipoprotein 3 (HDL3) and ascorbic acid (AsA) in combination on copper-catalyzed low density lipoprotein (LDL) peroxidation. LDL and HDL3 were isolated from sera of healthy volunteers. LDL protein, 200 microg/ml, was incubated in phosphate-buffered saline (PBS) containing 2.5 microM CuSO4 in the absence or presence of AsA, with HDL3 protein alone, or with coincubation of HDL3, 200 microg/ml, and AsA, 20 microg/ml, at 37 degrees C for up to 24 h. As a control, the same amount of control LDL protein was added to PBS. The protective effects of the HDL3 and AsA were examined by both electrophoresis and determination of the lipid hydroperoxide (LPO) level in each sample. The concentration of AsA was also measured in samples containing AsA. The coincubation of HDL3 and AsA exerts more powerful anti-peroxidative effects against copper-catalyzed LDL peroxidation, than either of these agents alone. In addition, AsA was retained in the media by the addition of HDL3. The findings suggest that there are strong synergistic anti-peroxidative effects of HDL3 and AsA and these two may act in concert in vivo to inhibit LDL peroxidation and thus exert an anti-atherosclerotic effect.

Molecular cloning and characterization of aldehyde oxidases in Arabidopsis thaliana

Using degenerate primers designed by deduced amino acid sequences of known aldehyde oxidases (AO) from maize and bovine, two independent cDNA fragments were amplified by reverse transcription-polymerase chain reaction (PCR). The two corresponding full-length cDNAs (atAO-1 and atAO-2; 4,484 and 4,228 bp long, respectively) were cloned by screening the Arabidopsis cDNA library followed by rapid amplification of cDNA end-PCR. These cDNAs are highly homologous at both the nucleotide and amino acid sequence levels, and the deduced amino acid sequences showed high similarity with those of maize and tomato AOs. They contain consensus sequences for two iron-sulfur centers and a molybdenum cofactor (MoCo)-binding domain. In addition, another cDNA having a sequence similar to that of the cDNAs was screened (atAO-3; 3,049 bp), and a putative AO gene (AC002376) was reported on chromosome 1, which (atAO-4) was distinct from, but very similar to, the above three AOs. atAO-1, 2, 3, and 4 were physically mapped on chromosomes 5, 3, 2 and 1, respectively. These data indicate that there is an AO multigene family in Arabidopsis. atAO-1 protein was shown to be highly similar to one of the maize AOs in respect to a region thought to be involved in determination of substrate specificity, suggesting that they might encode a similar type of AO, which could efficiently oxidize indole-3-acetaldehyde to indole-3-acetic acid (IAA). atAO-1 and atAO-2 genes were expressed at higher levels in lower hypocotyls and roots of the wild-type seedlings, while atAO-3 was slightly higher in cotyledons and upper hypocotyls. The expression of atAO-1 was more abundant in the seedlings of an IAA overproducing mutant (superroot1; sur1) than in those of wild type. atAO-2 and atAO-3 transcripts were rather evenly distributed in these seedlings. A possible involvement of atAO genes in phytohormone biosynthesis in Arabidopsis is discussed.

The GA2 locus of Arabidopsis thaliana encodes ent-kaurene synthase of gibberellin biosynthesis

The ga2 mutant of Arabidopsis thaliana is a gibberellin-deficient dwarf. Previous biochemical studies have suggested that the ga2 mutant is impaired in the conversion of copalyl diphosphate to ent-kaurene, which is catalyzed by ent-kaurene synthase (KS). Overexpression of the previously isolated KS cDNA from pumpkin (Cucurbita maxima) (CmKS) in the ga2 mutant was able to complement the mutant phenotype. A genomic clone coding for KS, AtKS, was isolated from A. thaliana using CmKS cDNA as a heterologous probe. The corresponding A. thaliana cDNA was isolated and expressed in Escherichia coli as a fusion protein. The fusion protein showed enzymatic activity that converted [3H]copalyl diphosphate to [3H]ent-kaurene. The recombinant AtKS protein derived from the ga2-1 mutant is truncated by 14 kD at the C-terminal end and does not contain significant KS activity in vitro. Sequence analysis revealed that a C-2099 to T base substitution, which converts Gln-678 codon to a stop codon, is present in the AtKS cDNA from the ga2-1 mutant. Taken together, our results show that the GA2 locus encodes KS.

Primary culture of cells from hyperfunctioning thyroid adenoma with an activating mutation of G alphas

We analyzed cultured cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue from a Japanese woman and determined the nucleotide sequences of genes encoding the alpha subunit of the stimulatory G-protein 1 (G alphas) and thyrotropin (TSH) receptor in its tumor tissue. Primary culture of cells from hyperfunctioning thyroid adenoma and its surrounding thyroid tissue revealed that cAMP production was constitutively activated while intracellular Ca2+ concentration was suppressed both at the basal level and in the response to TSH stimulation in the cells from tumor tissue compared with those from non-tumor tissue. Nucleotide sequence analysis demonstrated the somatic missense mutation at codon 201 (CGT(Arg)-CAT(His)) of G alphas gene in tumor tissue but not in its surrounding tissue. No mutation was observed in the transmembrane region of TSH receptor. These results suggest that cAMP regulatory cascade is constitutively activated while phospholipase C-Ca2+ signaling cascade is suppressed in hyperfunctioning thyroid adenoma with an activating mutation of G alphas gene in the present case.

Evaluation of coronary flow velocity dynamics and flow reserve in patients with Kawasaki disease by means of a Doppler guide wire

OBJECTIVES

To assess the pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables, we regionally evaluated the flow velocity dynamics and flow reserve in coronary vessels with lesions using an intracoronary Doppler flow guide wire.

BACKGROUND

The pathophysiologic effects of the coronary sequelae of Kawasaki disease on coronary hemodynamic variables have not been completely clarified, and we previously reported some discrepancies between coronary angiographic findings and exercise stress tests in Kawasaki disease.

METHODS

Doppler phasic coronary flow velocity was determined using an 0.018-in. (0.046-cm) intracoronary Doppler flow guide wire at rest and during the adenosine triphosphate-induced hyperemic response in 95 patients (75 male, 20 female, mean age 9.8+/-6.2 years) with Kawasaki disease.

RESULTS

In 25 patients with coronary aneurysms in 29 vessels, the average peak velocity and diastolic to systolic velocity ratio were significantly (p < 0.05) decreased in the moderate-sized and large-sized aneurysms. Significantly lower values in coronary flow reserve (CFR) were noted in 3 of 10 vessels with moderate aneurysms and in 4 of 7 vessels with large aneurysms. A significant positive correlation (y = 0.53x + 14.6, r2 = 0.91) was observed between the percent diameter stenosis evaluated by angiography and that calculated from the flow velocity measurement. However, the percent diameter stenosis calculated from the flow velocity measurement was underestimated compared with that determined by angiography in the stenotic lesions of intermediate severity. A reduced CFR was noted in five of seven vessels with intermediate stenosis ranging from 50% to 75%, and also in three vessels with mild stenosis ranging from 30% to 40%. A reduced CFR was also observed in six of the eight angiographically normal vessels associated with the area of reduced perfusion on exercise thallium-201 myocardial scintigraphy.

CONCLUSIONS

Abnormalities in flow dynamics and a reduction in flow reserve were revealed in coronary aneurysms of intermediate to large size and in stenotic lesions, even of mild to intermediate severity, in patients with Kawasaki disease. Abnormalities in the coronary microcirculation, as well as epicardial lesions, contribute to the pathophysiologic responses in Kawasaki disease.

Platelet epidermal growth factor in thyroid disorders

We evaluated the concentration of epidermal growth factor (EGF) in platelets, serum and plasma obtained from 47 patients with Graves' disease, 7 with hypothyroidism and 20 healthy subjects. The platelets of the subjects were collected from platelet rich plasma and lysed by freezing and thawing. Subsequently the platelet debris was treated with Triton X-100. The EGF concentration was determined by homologous radioimmunoassay. The concentration of EGF in the platelets in 14 patients with untreated Graves' disease was significantly higher than that in the healthy controls. After treating these 14 patients with antithyroid agents, the EGF concentration in the platelets decreased to the level of the healthy controls. The EGF concentration in the platelets in the 7 untreated hypothyroid patients decreased after replacement therapy with thyroxine. The mean volume of the platelets in the 14 patients with untreated Graves' disease was significantly larger than in the control and decreased after treatment with antithyroid agents. The serum and plasma levels of EGF in the 7 untreated hypothyroid increased after replacement therapy. In conclusion, thyroid function affected the concentration of EGF in the platelets of patients with thyroid disorders.

[Electrophysiologic evaluation of passive and active attentions--I. Topographic analysis of somatosensory event-related potentials]

We studied the topography of somatosensory event-related potentials (SERP) in two different attentive conditions: passive and active. Seventeen healthy right-handed young men, aged 19 to 28 years old (average age; 22.9 years), were requested to perform the following four paradigms in turn. In the passive attentive paradigm, participants were given no specific task when 0.3 Hz electrical stimuli were at random delivered to the right median nerve. In the active attentive paradigm, subjects were required to direct their attention to the regular 0.3 Hz stimuli with all their might. In the control paradigm. 2.0 Hz stimuli were delivered as they listened to their favorite music. Finally, in the oddball paradigm, subjects were instructed to push a button whenever they detected rare stimuli. SERP was recorded at 13 electrodes Grand average topographic amplitude maps from the individual data of the seventeen subjects were made at the latencies of N 60, P 90, N 130 and P 250 for each of the four paradigms. The topographic maps of P 250, the largest positive peak between 200 and 300 msec after the stimuli, showed a significant difference in the distribution of amplitude in the passive and active attentive paradigms compared to the control paradigm. A statistically significant enhancement was noted at the central region in the passive attention, and at the central and frontal regions in the active attention. These results suggest that P 250 consists of two attentive components distinct from selective or discriminative attention. The enhanced positivity at the frontal region during active attention may be associated with expecting the next stimulus and maintaining awareness.

Northern analysis of type II iodothyronine deiodinase mRNA in rat Harderian gland

It has been known that type II iodothyronine deiodinase activity is present in rat Harderian gland and the activity is significantly increased by isoproterenol administration. We have performed Northern analyses to study whether the transcript for type II iodothyronine deiodinase is expressed in rat Harderian gland and whether the isoproterenol stimulation of type II iodothyronine deiodinase activity in rat Harderian gland is due to the change in its mRNA level. Northern analyses have demonstrated that type II iodothyronine deiodinase mRNA, approximately 7.5 kb in size, is expressed in rat Harderian gland, and the mRNA levels as well as the deiodinase activities are greater in hypothyroid rats than those in euthyroid rats. Type II iodothyronine deiodinase mRNA levels and the deiodinase activities in Harderian gland were increased by isoproterenol administration, and the increase in the mRNA levels preceded that in the deiodinase activities. These results indicate that 7.5 kb transcript for type II iodothyronine deiodinase is expressed in rat Harderian gland and beta-adrenergic stimulation of type II iodothyronine deiodinase activity is due at least in part to the increase in its mRNA level.

[Electrophysiologic evaluation of passive and active attentions--II. Developmental changes of somatosensory event-related potentials in different attentive paradigms]

By somatosensory event-related potentials (SERP) we have previously demonstrated in adults that an enhanced positivity of P 250 is statistically significant at the frontal region during the active attentive state. We have also evaluated developmental changes of P 250 during different attentive states: passive and active. In this study, 30 healthy children (5-16 years of age) and six healthy adults (23-41 years) were required to perform the following four paradigms: passive attentive, active attentive, control, and oddball. SERP were recorded at Fz, Cz and Pz. In the passive attentive paradigm, P250 amplitude at Fz, Cz and Pz remained constant irrespective of age. With regard to the topography of the amplitude, however, P 250 was distributed dominantly at Pz in Group 1 (5-6 years of age) and Group 2 (7-11 years), contrary to the dominance at Cz in both Group 3 (12-16 years) and adults. In the active attentive paradigm, on the other hand, the P 250 amplitude at Fz reached its minimum at about 10 years and then increased until the adulthood. With respect to the topography of the amplitude, P 250 was distributed dominantly at Pz in Groups 1 and 2, at Cz in Group 3, and at Fz and Cz in adults. These results suggest that the topographic changes in the active attentive paradigm are dependent upon the developing abilities to expect the next stimulus and to maintain awareness.

Early intervention for very-low-birth-weight infants

To assess the efficacy of early intervention (EI) for very-low-birth-weight (VLBW) infants, we evaluated 62 2 year old children who were enrolled in an EI program and 48 control subjects aged 2 years. We determined the subjects' developmental quotients (DQ) and obtained information about the parents' evaluation of the children from a questionnaire sent to the parents. There was no significant difference in the DQ between the EI group and the control group. However, based on the responses to the questionnaire, subjects in the EI group showed slight, but statistically marginally significant, improvements in behavioral problems, especially a decrease in hyperkinesia, in adjusting to a circadian sleep cycle, and an improvement in language development, as compared with the control group (P < 0.1). Thus, EI for VLBW infants is considered useful to enhance some areas of development.

Differential effects of thiopental on neuronal nicotinic acetylcholine receptors and P2X purinergic receptors in PC12 cells

BACKGROUND

PC12 cells, derived from rat pheochromocytoma, express neuronal nicotinic acetylcholine receptors (nAchRs) and P2X purinergic receptors, both of which resemble the receptors in postganglionic sympathetic neurons. The former is the established and the latter is the putative receptor to mediate fast synaptic transmission. The authors investigated effects of thiopental on these two ligand-gated ion channels.

METHODS

Whole cell currents were recorded in PC12 cells without treatment of nerve growth factor, using conventional whole cell patch clamp technique. Nicotine or adenosine triphosphate (ATP) 30 microM was applied for 4-5 s in the absence or presence of thiopental 3-300 microM.

RESULTS

Nicotine induced the rapidly decaying inward current at -60 mV, which exhibited the characteristics of the neuronal nAchR-mediated current. Thiopental inhibited the nicotine-induced inward current and accelerated the current decay in a dose-dependent manner, resulting in the greater effects on the steady current than the peak current. IC50s for the peak and steady current were 56.7 and 7.4 microM, when the anesthetic was coapplied with nicotine. Thiopental's inhibition was not associated with a change in the reversal potential and was voltage-independent at membrane potential of -30 to -70 mV. Most of thiopental's effects seemed to require channel opening. In contrast to the nicotine-induced current, thiopental had little effect on the current elicited by ATP.

CONCLUSIONS

Thiopental, whose reported EC50 for general anesthesia is 25 microM, inhibited the neuronal nAchR-mediated current but not the P2X receptor-mediated response in PC12 cells at clinically relevant concentrations. Inhibition may result in suppression of synaptic transmission in sympathetic ganglia.

Cloning of the sdsA gene encoding solanesyl diphosphate synthase from Rhodobacter capsulatus and its functional expression in Escherichia coli and Saccharomyces cerevisiae

Different organisms produce different species of isoprenoid quinones, each with its own distinctive length. These differences in length are commonly exploited in microbial classification. The side chain length of quinone is determined by the nature of the polyprenyl diphosphate synthase that catalyzes the reaction. To determine if the side chain length of ubiquinone (UQ) has any distinct role to play in the metabolism of the cells in which it is found, we cloned the solanesyl diphosphate synthase gene (sdsA) from Rhodobacter capsulatus SB1003 and expressed it in Escherichia coli and Saccharomyces cerevisiae. Sequence analysis revealed that the sdsA gene encodes a 325-amino-acid protein which has similarity (27 to 40%) with other prenyl diphosphate synthases. Expression of the sdsA gene complemented a defect in the octaprenyl diphosphate synthase gene of E. coli and the nonrespiratory phenotype resulting from a defect in the hexaprenyl diphosphate synthase gene of S. cerevisiae. Both E. coli and S. cerevisiae expressing the sdsA gene mainly produced solanesyl diphosphate, which resulted in the synthesis of UQ-9 without any noticeable effect on the growth of the cells. Thus, it appears that UQ-9 can replace the function of UQ-8 in E. coli and UQ-6 in S. cerevisiae. Taken together with previous results, the results described here imply that the side chain length of UQ is not a critical factor for the survival of microorganisms.

Ent-kaurene synthase from the fungus Phaeosphaeria sp. L487. cDNA isolation, characterization, and bacterial expression of a bifunctional diterpene cyclase in fungal gibberellin biosynthesis

ent-Kaurene is the first cyclic diterpene intermediate of gibberellin biosynthesis in both plants and fungi. In plants, ent-kaurene is synthesized from geranylgeranyl diphosphate via copalyl diphosphate in a two-step cyclization catalyzed by copalyl diphosphate synthase and ent-kaurene synthase. A cell-free system of the fungus Phaeosphaeria sp. L487 converted labeled geranylgeranyl diphosphate to ent-kaurene. A cDNA fragment, which possibly encodes copalyl diphosphate synthase, was isolated by reverse transcription-polymerase chain reaction using degenerate primers based on the consensus motifs of plant enzymes. Translation of a full-length cDNA sequence isolated from the fungal cDNA library revealed an open reading frame for a 106-kDa polypeptide. The deduced amino acid sequence shared 24 and 21% identity with maize copalyl diphosphate synthase and pumpkin ent-kaurene synthase, respectively. A fusion protein produced by expression of the cDNA in Escherichia coli catalyzed the two-step cyclization of geranylgeranyl diphosphate to ent-kaurene. Amo-1618 completely inhibited the copalyl diphosphate synthase activity of the enzyme at 10(-6) M, whereas it did not inhibit the ent-kaurene synthase activity even at 10(-4) M. These results indicate that the fungus has a bifunctional diterpene cyclase that can convert geranylgeranyl diphosphate into ent-kaurene. They may be separate catalytic sites for the two cyclization reactions.

Cloning and molecular characterization of plant aldehyde oxidase

Primary structural information of a plant aldehyde oxidase (AO), which was purified from maize coleoptiles using indole-3-acetaldehyde as a substrate, was obtained by sequencing a series of cleavage peptides, permitting the cloning of the corresponding cDNA (zmAO-1). The complete nucleotide sequence was determined; the deduced amino acid sequence encodes a protein of 1358 amino acid residues of Mr 146,681, which is consistent with the size of the AO monomeric subunit. There is a significant similarity with AO from mammals and xanthine dehydrogenases from various sources. The maize AO polypeptide contains consensus sequences for iron-sulfur centers and a putative molybdopterin cofactor-binding domain. In addition, another cDNA (zmAO-2), highly homologous to zmAO-1 at both the nucleotide and amino acid sequence levels, was cloned. zmAO-2 would encode a protein of 1349 amino acid residues of Mr 145,173 and has molecular characteristics similar to those of zmAO-1. zmAO-1 was expressed at a high level in roots, which was closely correlated with immunoblotting results using antiserum raised against the purified maize AO protein, whereas zmAO-2 was expressed at a higher level in coleoptiles than in roots. We propose each zmAO may have a unique function during plant development.

Pneumocystis carinii pneumonia in Malawian children

Sixty children aged between 1 and 23 months admitted to Queen Elizabeth Central Hospital in Blantyre, Malawi for diagnosis of acute lower respiratory tract infections (ALRI) were investigated for laboratory diagnosis of Pneumocystis carinii pneumonia (PCP) by indirect immunofluorescence assay on nasopharyngeal secretions. P. carinii was found in five of the 60 children. Three PCP cases had AIDS. The clinical presentation of children with PCP was of little diagnostic value and all the children were infants. Arterial oxygen saturation was significantly lower in PCP cases. Of the five PCP cases, four died, indicating that the marked hypoxaemia was associated with poor prognosis. These results indicate that an immunofluorescence assay on nasopharyngeal secretions could be used for first-line diagnosis of PCP in Africa.

Expression and nocturnal increase of type II iodothyronine deiodinase mRNA in rat pineal gland

It has been demonstrated that thyroxine deiodinating activity is present in rat pineal gland, and its activity increases significantly during the night time. We have studied whether mRNA for type II iodothyronine deiodinase is expressed in rat pineal gland and whether the nocturnal rise of pineal T4 deiodinating activity is due to the change in type II iodothyronine deiodinase mRNA level. Reverse transcription-polymerase chain reaction amplification and Northern blot analyses have demonstrated that type II iodothyronine deiodinase mRNA is expressed in rat pineal gland and its mRNA level increases markedly at midnight. These results suggest that the nocturnal rise in pineal T4 deiodinating activity is due to the change in type II iodothyronine deiodinase mRNA level.

Analysis of the decaprenyl diphosphate synthase (dps) gene in fission yeast suggests a role of ubiquinone as an antioxidant

Schizosaccharomyces pombe produces ubiquinone-10 whose side chain is thought to be provided by the product generated by decaprenyl diphosphate synthase. To understand the mechanism of ubiquinone biosynthesis in S. pombe, we have cloned the gene encoding decaprenyl diphosphate synthase by the combination of PCR amplification of the fragment and subsequent library screening. The determined DNA sequence of the cloned gene, called dps, revealed that the dps gene encodes a 378-amino-acid protein that has the typical conserved regions observed in many polyprenyl diphosphate synthases. Computer-assisted homology search indicated that Dps is 45 and 33% identical with hexaprenyl diphosphate synthase from Saccharomyces cerevisiae and octaprenyl diphosphate synthase from Escherichia coli, respectively. An S. pombe dps-deficient strain was constructed. This disruptant was not able to synthesize ubiquinone and had no detectable decaprenyl diphosphate synthase activity, indicating that the dps gene is unique and responsible for ubiquinone biosynthesis. The S. pombe dps-deficient strain could not grow on either rich medium supplemented with glycerol or on minimal medium supplemented with glucose. The dps-deficient strain required cysteine or glutathione for full growth on the minimal medium. In addition, the dps-deficient strain is more sensitive to H2O2 and Cu2+ than the wild type. These results suggests a role of ubiquinone as an antioxidant in fission yeast cells.

Experiences and studies on antimicrobial resistance in Japan: useful lessons for developing countries

The use of antimicrobial drugs in Japan is remarkably high. In 1994, the total production cost of antimicrobial drugs amounted to 3.38 billion US dollars. The intensive use of broad-spectrum drugs, especially for treatment of increasing number of immunocompromised and elderly patients, resulted in the emergence and spread of antimicrobial-resistant organisms in Japan. A bacteriological study in a chronic care centre shows a variety of bacterial pathogens with increased antimicrobial resistance such as methicillin-resistant Staphylococcus aureus. Control measures of nosocomial infections with resistant organisms have been established and strengthened. This includes surveillance researches such as re-evaluation of disinfectants.

The LS locus of pea encodes the gibberellin biosynthesis enzyme ent-kaurene synthase A

Gibberellins (GAs) are hormones required for several aspects of plant development, including internode elongation and seed development in pea (Pisum sativum L.). The first committed step in the GA biosynthesis pathway is the conversion of geranylgeranyl diphosphate (GGDP) to ent-kaurene via copalyl diphosphate (CDP). These two reactions are catalyzed by the cyclases ent-kaurene synthase A (KSA) and ent-kaurene synthase B (KSB), respectively. Previous genetic and biochemical analysis of the GA-responsive ls-1 mutant of pea suggested that GA levels are reduced in a developmental- and organ-specific manner due to reduced GA biosynthesis. Analysis of cellfree enzyme preparations from WT and ls-1 embryos at contact point reveals that ls-1 reduces the activity of KSA but not KSB. To characterize the ls-1 mutation in more detail, a cDNA coding for a pea KSA was cloned and shown to be encoded by the LS locus. The ls-1 mutation results from an intronic G to A substitution that causes impaired RNA splicing. To determine the activity of the KSAs encoded by the LS and ls-1 alleles, a new in vitro assay for combined KSA and KSB activity has been developed using the KSB gene of pumpkin. Using recombinant WT KSA and KSB fusion proteins, GGDP is converted to ent-kaurene in vitro. Based on the sequence of RT-PCR products, three different truncated KSA proteins are predicted to exist in ls-1 plants. The most abundant mutant KSA protein does not possess detectable activity in vitro. Nevertheless, the ls-1 allele is not null and is able to encode at least a partially functional KSA since a more severe is allele has been identified. The ls-1 mutation has played a key role in identifying a role for GAs in pea seed development in the first few days after fertilization, but not in older seeds. KSA expression in seeds is developmentally regulated and parallels overall GA biosynthesis, suggesting that KSA expression may play an important role in the regulation of GA biosynthesis and seed development.

[The effects of preventive regimens for the prophylaxis of infection after bone marrow transplantation]

The effects of regimens on the prevention of infection in 42 adult leukemia patients receiving bone marrow transplantation was analyzed. Standard risk patients (transplantation in 1st remission of acute leukemia and chronic phase of chronic myelogeneous leukemia received marrow from HLA compatible sibling or autologous marrow) showed shorter febrile days than high risk patients (transplantation in more advanced stage of leukemia and transplantation from unrelated donor), 1.33 mean days vs. 4.93 mean days respectively. Poorer intake of non-absorved antibiotics resulted in higher rate of bacterial colonization in stool after transplantation. And that, the degree of gut sterilization correlated with the duration of febrile days during the period of less than 100/microliter peripheral neutrophil count in high risk patients. Thus, prophylactic regimens of infection in bone marrow transplantation should be considered according to the risk of patient, that is, more practical and complete prophylaxis in risk patients and more conventional one in standard risk patients.

Effects of dehydroepiandrosterone on proliferation of human aortic smooth muscle cells

Dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) have been shown to be associated with the progression of coronary atherosclerosis in clinical and in vivo studies. However, the mechanisms responsible for the association have not been determined. In the present study, we found that DHEA influences the in vitro growth of vascular smooth muscle cells obtained from the human aorta (hASMC). The concentrations of DHEA ranging from 10(-8) M to 10(-6) M significantly stimulated the mitogenesis of hASMC in serum-free culture. On the other hand, 4 hrs of pretreatment with DHEA attenuated the fetal calf serum induced proliferative effect in a dose-dependent manner. However, the in vitro effects of DHEA on the mitogenesis observed in hASMC were not seen in rat-derived aortic smooth muscle cell lines (A10 cells). With respect to DHEAS, the hormone, at concentrations up to 10(-5) M did not affect the growth of either hASMC or A10 cells in vitro. The growth response of hASMC to DHEA in vitro was markedly affected by the culture conditions. The differential proliferative effects of DHEA on smooth muscle cells between rat and human are of interest. We conclude that the effects of DHEA on mitogenesis of hASMC may, at least in part, explain the association between DHEA and atherosclerosis.

[Efficacy and side effects of lidocaine by intravenous drip infusion in children with intractable seizures]

Intravenous drip infusions of lidocaine (IDIL; 1-5 mg/kg/h) were performed in ten patients with intractable seizures. The medication was very effective in five patients, whose seizures disappeared immediately after the treatment of IDIL. In four patients, the medication proved to be effective judging from decreased incidence of seizures. In one patient with intractable seizures, the therapy was not effective. In nine patients with the effective medication, five had generalized seizures and four had partial seizures. Side effects were observed in four patients. Two patients had muscle hypotonia, one had visual and auditory hallucination and another had bradycardia. These symptoms completely disappeared after the ceasing of IDIL. Serum concentrations of lidocaine at the appearance of the side effects ranged from 1.8 to 4.7 micrograms/ml, although the toxicity level is more than 5.0 micrograms/ml for arrhythmic adult patients. These findings suggest that the serum toxic level of lidocaine in children is different from that in adults, and that careful observation and appropriate management for the children with lidocaine therapy should be necessary, even though the serum level of lidocaine ranges within the therapeutic level.

[Cerebral cortical dysplasia associated with epilepsy: MRI and clinical aspects]

Clinical and electroencephalographic (EEG) studies were performed in nine patients with cerebral cortical dysplasia (CD). Interictal single photon emission computed tomography (SPECT) using 99mTc-hexamethyl propylene amine oxime were studied in four patients. A patient with hemimegalencephaly and agyria had poor outcome in both developmental and epileptic aspects. The prognoses of clinical seizures were generally related to the severity, location and size of CD. The size of the lesion was not always correlated with the clinical seizure outcome. Four patients had focal pachygyria. Clinical pictures were diverse in these patients. One patient underwent callosotomy for the control of intractable seizures. The others had no clinical seizures despite of the appearance of paradoxical discharges in the area of pachygyria. The distribution of CD detected by MRI did not always correlate with that of paradoxical discharges in EEG and/or hypoperfusional areas seen in SPECT. These findings suggest that a detailed neuroimaging study is useful to elucidate the epileptogenesis in patients with CD, and that all the cortical abnormalities in patients with intractable epilepsy are not detected by MRI.

Thymic hyperplasia in patients with Graves' disease. Identification of thyrotropin receptors in human thymus

Thymic size and density were studied in 23 untreated patients with Graves' disease and 38 control subjects using computed tomography. Both thymic size and density were higher in untreated patients with Graves' disease than in control subjects in the age-matched group. After treatment with antithyroid drugs, both thymic size and density were significantly reduced, with a concomitant decrease in thyrotropin receptor antibodies. PCR of human thymic cDNA using primers for human thyrotropin receptor amplified a fragment in a size expected for the receptor, and its nucleotide sequence was identical to human thyrotropin receptor cDNA in the thyroid. Northern blot analysis of human thymic poly(A)+ RNA demonstrated the presence of the full length form of thyrotropin receptor mRNA. Western blot analysis of human thymic membrane using anti-thyrotropin receptor peptide antibodies demonstrated a band of 100 kD that was also observed in the thyroid membrane. Immunohistochemistry of thymic tissue using mouse antihuman thyrotropin receptor monoclonal antibodies demonstrated the immunostaining of epithelial cells. These results indicate that thymic hyperplasia is apparently associated with Graves' disease and suggest that thymic thyrotropin receptor may act as an autoantigen that may be involved in the pathophysiology of development of Graves' disease.

Polyprenyl diphosphate synthase essentially defines the length of the side chain of ubiquinone

Ubiquinone, known as a component of the electron transfer system in many organisms, has a different length of the isoprenoid side chain depending on the species, e.g., Escherichia coli, Saccharomyces cerevisiae and humans have 8, 6, and 10 isoprene units in the side chain, respectively. No direct evidence has yet shown what factors define the length of the side chain of ubiquinone. Here we proved that the polyprenyl diphosphate that was available in cells determined the length of the side chain of ubiquinone. E. coli octaprenyl diphosphate synthase (IspB) was expressed with the mitochondrial import signal in S. cerevisiae. Such cells produced ubiquinone-8 in addition to the originally existing ubiquinone-6. When IspB was expressed in a S. cerevisiae COQ1 defective strain. IspB complemented the defect of the growth on the non-fermentable carbon source. Those cells had the activity of octaprenyl diphosphate synthase and produced only ubiquinone-8. These results opened the possibility of producing the type of ubiquinone that we need in S. cerevisiae simply by expressing the corresponding polyprenyl diphosphate synthase.

Molecular cloning and characterization of a cDNA encoding the gibberellin biosynthetic enzyme ent-kaurene synthase B from pumpkin (Cucurbita maxima L.)

The first committed step in the formation of diterpenoids leading to gibberellin (GA) biosynthesis is the conversion of geranylgeranyl diphosphate (GGDP) to ent-kaurene. ent-Kaurene synthase A (KSA) catalyzes the conversion of GGDP to copalyl diphosphate (CDP), which is subsequently converted to ent-kaurene by ent-kaurene synthase B (KSB). A full-length KSB cDNA was isolated from developing cotyledons in immature seeds of pumpkin (Cucurbita maxima L.). Degenerate oligonucleotide primers were designed from the amino acid sequences obtained from the purified protein to amplify a cDNA fragment, which was used for library screening. The isolated full-length cDNA was expressed in Escherichia coli as a fusion protein, which demonstrated the KSB activity to cyclize [3H]CDP to [3H]ent-kaurene. The KSB transcript was most abundant in growing tissues, but was detected in every organ in pumpkin seedlings. The deduced amino acid sequence shares significant homology with other terpene cyclases, including the conserved DDXXD motif, a putative divalent metal ion-diphosphate complex binding site. A putative transit peptide sequence that may target the translated product into the plastids is present in the N-terminal region.

Effects of fructose ingestion on sorbitol and fructose 3-phosphate contents of erythrocytes from healthy men

To investigate the effect of fructose ingestion on sorbitol and fructose 3-phosphate (F3P) in erythrocytes, we administered 50 g fructose with and without treatment with an aldose reductase inhibitor, epalrestat, to seven healthy, normal-glucose-tolerant, male volunteers aged 20-43 years. The same subjects were given 50 g glucose on another day. The sorbitol and F3P contents in their erythrocytes increased significantly, reaching peak levels at 60 min and 180 min, respectively, following fructose in gestion. On the other hand, glucose ingestion did not cause any statistically significant change in sorbitol content in their erythrocytes, although it significantly elevated their F3P content. Treatment with epalrestat had no significant effect on incremental changes in erythrocyte sorbitol and F3P content following fructose ingestion. This suggests that oral fructose may be converted directly to sorbitol and F3P in erythrocytes instead of being converted via glucose. Thus, the dietary intake of fructose may affect the concentrations of sorbitol and F3P in erythrocytes in normal men.

Single application extracorporeal shock wave lithotripsy is the first choice for patients with pancreatic duct stones

OBJECTIVES

We performed extracorporeal shock wave lithotripsy (ESWL) as the treatment of first choice on 32 chronic pancreatitis patients with main pancreatic duct (MPD) stones prospectively to establish more convenient and safer treatment.

METHODS

All patients were treated in a prone position, and shock waves were discharged from the ventral side. ESWL was performed once or twice a week, and no other treatments before ESWL had been applied.

RESULTS

Disintegration of all MPD stones to 3 mm or less in diameter could be achieved in all treated patients. Complete clearance of the stones was obtained in 24 patients (75%) without the necessity of endoscopic extraction of fragments. Reduction of MPD diameters after ESWL was statistically significant (p < 0.01). Epigastric and/or back pain complaints before ESWL were completely alleviated in 79% (periods of follow-up: 16-63 months, mean 44), and the pancreatic exocrine function also improved in 61%. No severe complications occurred in any of the patients.

CONCLUSIONS

ESWL, which is comparatively easy to perform, is a safe and efficient approach that changes endoscopy's status as an indispensable pretreatment. Therefore, ESWL can be recommended as the first choice treatment for patients with chronic pancreatitis accompanied by MPD stones that should be tried before consideration of either surgical or endoscopic procedures.

[A successful treatment with a continuous intravenous lidocaine for a cluster of minor seizures in a patient with Doose syndrome]

We reported a 7-year-old girl with myoclonic-astatic epilepsy of early childhood (Doose syndrome). She had minor seizures (i. e. absence, atonic and myoclonic seizures) refractory to treatment with many kinds of anti-epileptic drugs as well as thyrotropin releasing hormone. Though she had suffered from long-lasting clusters of minor seizures, the treatment with continuous intravenous lidocaine successfully brought a case of prolonged remission of both clinical seizures and EEG abnormalities. It has been reported that lidocaine is effective mainly for partial seizures. The efficacy of lidocaine for generalize seizures, however, has been reported only in a few papers. We considered that the treatment with continuous intravenous lidocaine is indicated in patients with Doose syndrome presenting with a cluster of refractory minor seizures.

Lead levels and related biochemical findings occurring in Ghanaian subjects occupationally exposed to lead

Blood and urine lead levels in relation to blood delta-aminolevulinic acid dehydratase (ALAD) activity and also blood and renal status were evaluated in lead smelters, automobile mechanics and gasoline retailers in the city of Accra, Ghana. Relationship between high blood lead levels (mean: 108 ug/dl) and low ALAD activity (mean: 74.3 units) indicating lead over exposure was found in the lead smelters. Non-toxic lead exposure was, however, noted in the automobile mechanics and the gasoline retailers. Their respective mean blood lead levels were 27.8 ug/dl (mean blood ALAD activity 212.5 units) and 8.6 ug/dl (ALAD: 239.9 units). Personal habits at the work place appear to play a major role in facilitating exposure to lead among all the three groups of workers in addition to lack of control measures at the work place of the lead smelters to protect them against lead exposure. Anaemia was found in 48% of the lead smelters, 12.5% of the gasoline retailers but in none of the automobile mechanics. When compared with lead free subjects (mean blood ALAD activity: 270.9 units), urine microalbumin was significantly (p < 0.01) raised in all the lead smelters suggesting that they may be prone to renal glomerular damage. Plasma creatinine, BUN and uric acid were raised in only one of the lead smelters. The data supports the establishment of blood ALAD activity level at 100 units or less as indication of excessive body lead.

Bile secretion in rats with indomethacin-induced intestinal inflammation

The objective of this study was to characterize the bile secretion, including the composition of biliary bile acids, bile salt pool size, and transcytotic vesicle transport, in a rat model of subacute intestinal inflammation induced by indomethacin. Indomethacin treatment significantly decreased bile acid-independent bile flow and biliary secretion of bile acid and cholesterol, while increasing biliary phospholipid output in vivo. Although indomethacin treatment did not change the bile salt pool size in vivo, alpha- and beta-muricholic acids were significantly deceased and hyodeoxycholic and deoxycholic acids were increased in bile. Bile flow and the transport maximum of taurocholate did not decrease, and biliary horseradish peroxidase output was significantly enhanced in isolated perfused livers from indomethacin-treated rats. Endotoxin in the portal blood was significantly increased in rats treated with indomethacin. Clindamycin slightly reduced intestinal inflammation but significantly prevented decreases in bile flow, bile acid output, and transport maximum of taurocholate. We conclude that, although biliary secretory function was apparently decreased in vivo, that of hepatocyte function was maintained in this model.