Assignment of disulfide bond location in prothoracicotropic hormone of the silkworm, Bombyx mori: a homodimeric peptide

The disulfide bond location of a homodimeric peptide, prothoracicotropic hormone (PTTH) of the silkworm, Bombyx mori, was determined by a combination of partial reduction and sequence analysis of peptide fragments generated through a partial reduction of PTTH followed by alkylation and enzyme digestion. The partial reduction and S-alkylation broke the interchain disulfide bond but did not affect the intrachain disulfide bonds, generating monomeric PTTH whose intrachain disulfide bonds were kept intact. This monomeric PTTH has about one-half the biological activity of intact PTTH. Sequence analysis of the fragments generated by lysyl endopeptidase digestion of this monomeric PTTH after complete reduction and S-alkylation by another S-alkylating reagent showed that only the Cys15 residue was reduced and S-alkylated by the foregoing partial reduction, indicating that this residue formed the interchain disulfide bond. The other disulfide bonds which formed intrachain bridgings were determined by sequence and mass analyses of the fragments generated by two successive enzyme digestions of the monomeric PTTH. In conclusion, the disulfide bond location of PTTH was assigned to Cys15-Cys15' as an interchain disulfide linkage and Cys17-Cys54, Cys40-Cys96, and Cys48-Cys98 as intrachain disulfide linkages.

[Determination of new anticancer drug, paclitaxel, in biological fluids by high performance liquid chromatography]

A simple and reproducible high performance liquid chromatographic (HPLC) method using an internal standard (I.S.) was developed for the determination of an anticancer drug, paclitaxel, in biological fluids. The sample preparation involves a solid-phase extraction step. HPLC was performed on an ODS column using acetonitrile-2 mM phosphoric acid (45:55) as a mobile phase with detection at 227 nm. A linear relationship was obtained in the range of 0.02-2.0 micrograms/ml in the rat plasma and urine. Since the recovery of the drug was as high as that of I.S. (> 96%), a standard curve generated from the solution of the drug with I.S. in the mobile phase could be used for determination. The method could be applicable for human and dog plasma as well as rat plasma, and the intra- and interday coefficients of variation at 0.05, 2.0 and 10.0 micrograms/ml were less than 7%. This method is useful for pharmacokinetic studies of paclitaxel.

The effect of betamethasone on myocardial viability during cold cardioplegia in canine donor heart preservation

This study examined the effect of betamethasone on myocardial viability of reperfused isolated canine hearts following a 6-h hypothermic cardioplegia. The dogs were divided into two groups: group I (n = 9) received nondepolarizing cardioplegia containing betamethasone 250 mg/l while group II (n = 7) was administered cardioplegia without betamethasone. The myocardial concentrations of calcium, ATP, ADP, total adenine nucleotide, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were identical in the two groups throughout the experiment. The coronary sinus plasma concentrations of MB fraction of creatine kinase (MB-CK), cAMP and cGMP after 2h of reperfusion were significantly lower in group I than in group II. The myocardial mitochondrial ultrastructure, as assessed by semiquantitative morphometry, was found to be significantly better preserved in group I than in group II at the end of both preservation and reperfusion. In addition, the left ventricular end-systolic pressure volume relation (ESPVR) showed a higher slope and lower intercept in group I than in group II. These results suggest that the addition of betamethasone to nondepolarizing cold cardioplegia enhances myocardial protection via membrane stabilization without affecting the adenine nucleotide metabolism.

Effects of electrical pacing to the preischemic rate during rewarming after hypothermic ischemia in the rat heart

The effects of electrical pacing during the early reperfusion following hypothermic global ischemia (60 min, at 25 degrees C) was studied in the isolated working rat heart model. The hearts were divided into three groups. Hearts in Group I (n = 8) were control without hypothermia, ischemia or pacing. Hearts in Group II (n = 16) were paced with ventricular rate at 300 beats/min with 1 mVolt for 10 min during the Langendorff mode after an initial 5 min of reperfusion. Hearts in Group III (n = 14) were not paced. The recovery of aortic flow (both absolute and percent) was significantly better in Group II than in Group III, but was significantly lower in both groups than in control. No significant differences were noted, however, in heart rate, aortic pressure or coronary flow between Group II and III. In contrast, the tissue concentration of adenosine triphosphate (ATP) in Groups II and III decreased significantly by the end of reperfusion relative to Group I, but no difference in ATP existed between Group II and III. Myocardial ATP concentrations did not correlate with percent recovery of aortic flow. The myocardial concentration of calcium in Groups II and III increased by the end of reperfusion as compared with Group I, but no difference in calcium existed between Group II and III. The myocardial concentration of calcium demonstrated a significant correlation with percent recovery of aortic flow (r = 0.71, n = 30, p < 0.005). Our results indicate that an electrical pacing during early reperfusion in the myocardium improves functional recovery of aortic flow.

[Hodgkin's disease initially presenting as vertebral lesions and a solitary pulmonary nodule--a case report]

Hodgkin's disease rarely involves bones and lungs without causing marked lymph node enlargement. The case of a 36 year old man, who initially presented with vertebral lesions and a solitary nodule in the lung, is reported. At the initial presentation, no apparent lymph node enlargement was observed. Pathological examination of the specimens obtained at vertebral surgery and needle biopsy of the lung suggested a presumptive diagnosis of Histiocytosis X. However, a definite diagnosis of the Hodgkin's disease was made by biopsy of a cervical lymph node which newly enlarged about two years after his initial presentation. This case suggests variability in the clinical feature of Hodgkin's disease.

The sequences of S-glycoproteins involved in self-incompatibility of Brassica campestris and their distribution among Brassicaceae

S-Glycoproteins have been thought to play a role in the self-incompatibility in Brassica plants. Two cDNAs encoding S-glycoproteins were isolated from stigmas of two strains of Brassica campestris. Their amino acid sequences are highly homologous to each other. However, the numbers of the potential glycosylation sites are different, although most of them are conserved. In the middle part of the sequences, there are two supervariable regions which might contribute to the specificity of each S-glycoprotein. Genomic Southern analysis showed many bands hybridizing with cDNA of S-glycoproteins in various Brassica species including self-compatible species.

[Construction of a short-form of the scale of egalitarian sex role attitudes (SESRA-S)]

This article describes the construction of a 15-item short-form of the Scale of Egalitarian Sex Role Attitudes (SESRA-S) based on factor analysis and examines the reliability and the validity of the short-form using data from a sample of 109 men and 93 women. SESRA-S is a self-report measure of the level of egalitarian attitudes toward the roles of men and women. Its reliability coefficient was .91, the test-retest coefficient with a four-week interval .89, and the correlation coefficient with the full form .94. These support the reliability of the short-form. Evidence of the construct validity was derived from the confirmation of five hypotheses regarding gender, educational attainment, women's employment status, age, and surname change after marriage. The findings of the present study provide evidence for the utility of the short-form as a satisfactory and time-efficient substitute for the SESRA full form.

The myocardial distribution and plasma concentration of carnitine in patients with mitral valve disease

The myocardial distribution and concentration of carnitine and its fractions was studied in 11 patients with mitral valve disease not associated with congestive heart failure (CHF). The plasma concentration of carnitine was found to be identical to the normal values documented in the literature. The left ventricular papillary muscle had the highest concentrations of total, short-acyl, long-acyl, and free carnitine, being significantly higher than those of the right ventricle, while the right atrial appendage had the lowest values of all fractions of carnitine. The proportion of long-acyl carnitine to total carnitine was significantly greater in the left ventricle than in either the right atrium or the atrial septum, and other carnitine fractions were identical in all cardiac chambers. Our results suggest that in the compensated heart with mitral valve disease, carnitine and its fractions are greatest in the left ventricle in the muscles of all cardiac chambers, and that long-acyl carnitine is most likely to be linked to the cardiac muscle demanding a higher cardiac performance.

[A case of micro-metastatic lung adenocarcinoma into adenoma of the thyroid]

In a case of 46-year-old woman, small nodules appeared in the anterior neck which was diagnosed as follicular adenoma of the left lower lobe of the thyroid. Four months before, she experienced resection of the lung and three courses chemotherapy of MVP for stage IIIb well-differentiated lung adenocarcinoma. Pathologically, micro-metastatic lung adenocarcinoma was found in the adenoma. It is very rare occurrence for lung carcinoma to metastasize into adenoma of the thyroid. But when tumors of the anterior neck are found in a patient of lung carcinoma, thyroid tumor must be considered for differential diagnosis.

[Case report: infective endocarditis caused by Streptococcus agalactiae]

A 42-year-old male was admitted to our hospital because of high grade fever on October 6, 1992. He had no history of cardiac and underlying disease. For the past 10 days, he had complained of high grade fever and noticed arthralgia on his left shoulder. Physical examination on admission revealed that there was a body temperature of 39.0 degrees C and tenderness in the left shoulder. There were no abnormal findings for the chest or abdomen. On the second hospital day, he developed a diastolic murmur which had not been present on admission. And blood culture was positive for Streptococcus agalactiae. Ultrasonic-cardiogram indicated the presence of vegetation. He was diagnosed as infective endocarditis and treated with PCG 20 million units/day, IPM/CS 2 g/day and ISP 400 mg/day. But he was not responding to the chemotherapy. Aortic valve replacement was done on 22nd, October. Valve surgery succeeded and he became well after that time. Endocarditis caused by S. agalactiae is extremely rare, and is an important condition which carries a high mortality. Only seven cases of S. agalactiae endocarditis have been reported in Japan. It is difficult to treat these cases with antibiotic therapy alone. Therefore, we suggest that early surgery should be considered in infective endocarditis caused by S. agalactiae.

[Review of cases of ruptured cerebral aneurysm with a history of examination at our institution prior to the diagnosis of subarachnoid hemorrhage--in order to improve treatment outcome in patients with intracranial aneurysms]

There were 78 patients who had been examined at our institution prior to the diagnosis of subarachnoid hemorrhage (SAH) among the 1114 patients with ruptured aneurysm stet between April 1974 and March 1992. Among these 78 cases these were 35 patients who might have been treated at an earlier stage, i.e., 26 patients in which the diagnosis was made belatedly and 9 patients in which an unruptured aneurysm was missed. All 26 patients with belatedly diagnosed SAH had headache without neck stiffness or neurological deficits and thus were Hunt and Kosnic grade 1-2 while 25 cases were categorized so called "minor leak". The causes in 6 of the 7 patients with poor outcome was rerupture or vasospasm due to delay in the diagnosis of SAH. Because the diagnosis of mild SAH is not always easy, it is important to take a careful medical history. MRI or lumbar puncture should be performed when SAH is suspected from the history, even if CT shows no evidence of SAH. The cause of failure to diagnose unruptured aneurysms, in addition to misreading was blood vessel overlapping as a result of non-selective angiography, poor contrast, etc. Angiography should be performed selectively and the inclusion of oblique, magnified, stereoscopic, and other imaging techniques is advisable, if an unruptured aneurysm is suspected, and angiographic follow-up is necessary when an ruptured aneurysm is uncertain.

Multifactorial modeling for root caries prediction: 3-year follow-up results

The study was part of a series aiming at the development of caries tests. The initial material (n = 104, age range 47-79 yr, mean 62 yr) was reduced to 96, who were observed for 3 yr. During the follow-up four subjects died, all due to myocardial infarction, and four refused to participate. Thorough oral examinations were conducted at the baseline, 1- and 3-yr registrations; coronal and root surface caries were registered separately according to WHO classification. The tests included salivary mutans streptococci, lactobacilli, candida/yeasts, secretion rate, buffer effect and sucrase activity, and quantitation of visible plaque. The association between prospective root caries increment and several tests was significant. Multifactorial modeling resulted in the combination of Past Root Caries Experience (OR 12.8), Lactobacilli (OR 8.6) and Candida (OR 2.8). At screening, the criterion "two or three positive tests" of these yielded acceptable accuracy (77.1) and a relative risk of 3.3.

The effect of L-carnitine on myocardial protection in cold cardioplegia followed by reperfusion

We studied the effect of exogenous L-carnitine on myocardial viability and carnitine uptake following ischemia-reperfusion in isolated rat hearts. Hearts were subjected to hypothermic cardioplegia at 26 degrees C for 80 minutes with and without carnitine 10 mmol/L added to the perfusate and cardioplegic solution [Groups I (n = 9) and II (n = 14), respectively]. Additionally, to study myocardial carnitine uptake, hearts were subjected to global ischemia at 20 degrees C [Group III (n = 6) and IV (n = 6)] and at 37 degrees C [Group V (n = 6) and VI (n = 6)] with and without carnitine 10 mmol/L added to the perfusate. All hearts received normothermic reperfusion, and Krebs-Henseleit solution was used as the perfusate in all groups. Postischemic aortic flow, expressed as the percentage of pre-ischemic flow, morphometric scores of myocardial mitochondria, and the myocardial concentration of adenosine triphosphate at the end of reperfusion were significantly higher in Group I than in Group II. In hearts treated with L-carnitine both at 20 degrees C and 37 degrees C the myocardial concentrations of carnitine fractions (free, short-acyl, and long-acyl) increased significantly compared to those in hearts without L-carnitine treatment. The myocardial concentration of free carnitine at the end of reperfusion was significantly higher in Group III than at pre-ischemia. These results suggest that exogenous L-carnitine is incorporated into cellular metabolism, even in hypothermic cardioplegia, improving cardiac function and preserving the myocardial adenosine triphosphate concentration.

Effects of cardiac denervation on coronary and systemic circulation

The effects of cardiac denervation on coronary circulation and systemic hemodynamics were examined in patients who underwent coronary artery bypass grafting for a totally occluded left anterior descending coronary artery. The results in 14 patients who had undergone a combination of bypass grafting and intrapericardial denervation (group I) were compared with those in 19 patients who had undergone only bypass grafting (group II). The heart rate was 110 +/- 4.9 beats/min in group I and 104 +/- 3.7 beats/min in group II after denervation. Although the cardiac index was not significantly different between the two groups, the calculated systemic vascular resistance index of group I (1,358 +/- 111 dynes.s.cm-5.m2) was significantly lower (p < 0.02) than that in group II (1,713 +/- 75 dynes.s.cm-5.m2). The end-diastolic coronary resistance was significantly lower (p < 0.05) in group I (0.59 +/- 0.05 mm Hg.mL-1.min-1) than that in group II (1.04 +/- 0.14 mm Hg.mL-1.min-1), and the end-diastolic graft flow/mean graft flow ratio was 1.56 +/- 0.05 in group I and 1.28 +/- 0.04 in group II (p < 0.01). The plasma norepinephrine concentration in group I (223 +/- 52 pg/mL) was significantly low (p < 0.05) compared with that in group II (328 +/- 39 pg/mL) after denervation. Thus, cardiac denervation may have a beneficial effect on systemic hemodynamics and coronary circulation.

Effect of prostaglandin F2 alpha on Ca2+ influx in osteoblast-like cells: function of tyrosine kinase

We previously reported that pertussis toxin-sensitive GTP-binding protein is involved in prostaglandin F2 alpha (PGF2 alpha)-induced phosphoinositide (PI) hydrolysis in osteoblast-like MC3T3-E1 cells [Miwa et al. (1990): Biochem Biophys Res Commun 171:1229-1235]. In the present study, we investigated the mechanism of PGF2 alpha-induced Ca2+ influx in MC3T3-E1 cells. PGF2 alpha-induced formation of total inositol phosphates (IPs) was markedly reduced by the depletion of extracellular Ca2+ with EGTA. On the other hand, the depletion of extracellular Ca2+ had little effect on PGF2 alpha-induced inositol 1,4,5-trisphosphate formation. PGF2 alpha stimulated 45Ca2+ influx dose dependently, attaining a maximum effect at 10 nM. Dose of PGF2 alpha above 10 nM caused less than maximal stimulation. Genistein, an inhibitor of protein tyrosine kinase, which by itself had little effect on 45Ca2+ influx, significantly suppressed the PGF2 alpha-induced 45Ca2+ influx in a dose-dependent manner in the range between 1 micrograms/ml and 0.1 mg/ml. Sodium orthovanadate, an inhibitor of protein tyrosine phosphatases, enhanced the PGF2 alpha-induced 45Ca2+ influx. Genistein also suppressed the PGF2 alpha-induced total IPs formation dose dependently in the range between 1 micrograms/ml and 0.1 mg/ml. However, it had little effect on the PGF2 alpha-induced inositol 1,4,5-trisphosphate formation. The pretreatment with pertussis toxin had little effect on the PGF2 alpha-induced 45Ca2+ influx. These results strongly suggest that PGF2 alpha stimulates Ca2+ mobilization from extracellular space and PI hydrolysis via independent pathways in osteoblast-like cells, and the PGF2 alpha-induced Ca2+ influx is regulated by protein tyrosine kinase, resulting in the promotion of PI hydrolysis.

Expression of alpha-1,3 linkage-containing oligomannosyl residues in a cell-wall mannan of Candida tropicalis grown in yeast extract-Sabouraud liquid medium under acidic conditions

We investigated the cell-wall mannan obtained from Candida tropicalis IFO 1647 strain cells grown in yeast extract-Sabouraud medium at pH 3.0 by two-dimensional homonuclear Hartmann-Hahn spectroscopy. The results indicate that the phosphate group and the side chains containing a beta-1,2-linked mannopyranose unit decreased compared to those of mannan from cells grown under conventional conditions (pH 5.9) with concomitant expression of alpha-1,3 linkage-containing oligomannosyl side chains. The results of acetolysis of these mannans indicated that the presence of alpha-1,3-linked mannopyranose unit existed in side chains corresponding to pentaose and hexaose, Manp alpha 1-3 Manp alpha 1-2Manp alpha 1-2 Manp alpha 1-2Man, and Manp alpha 1-2Manp alpha 1-3Manp alpha 1-2Manp alpha 1-2Manp alpha 1-2Man, in the mannan from cells grown at pH 3.0.

Biosynthesis of N-glycolylneuraminic acid-containing glycoconjugates. Purification and characterization of the key enzyme of the cytidine monophospho-N-acetylneuraminic acid hydroxylation system

We have proposed that cytidine monophospho-N-acetylneuraminic acid (CMP-NeuAc) hydroxylation is carried out by a multienzyme system involving CMP-NeuAc hydroxylase (the terminal enzyme of the system), cytochrome b5, and an NADH-dependent cytochrome b5-reducing factor (Kozutsumi, Y., Kawano, T., Yamakawa, T., and Suzuki, A. (1990) J. Biochem. 108, 704-706). The CMP-NeuAc hydroxylase was purified to homogeneity from the cytosolic fraction of mouse liver, using ion exchange columns, a Red-Sepharose column, and a soluble cytochrome b5-immobilized Sepharose column. The purified enzyme exhibited a single band (64 kDa) on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a single peak (58 kDa) on gel permeation chromatography, indicating that it is composed of a single polypeptide chain. The absorption spectrum did not indicate the presence of a heme prosthetic group in the enzyme. Atomic absorption spectrometry and an inhibition test using an iron chelator indicate that the enzyme contains non-heme iron as an electron acceptor. A reconstitution experiment with the purified CMP-NeuAc hydroxylase, soluble cytochrome b5, and recombinant NADH-cytochrome b5 reductase revealed that these three factors are essential for the reaction. The hydroxylase exhibited high affinity to CMP-NeuAc (Km = 5 microM) and was greatly stabilized by CMP-NeuAc. The molecular activity of the enzyme (approximately 500/min) is much lower than that reported for NADH-cytochrome b5 reductase, suggesting that the activity or amount of hydroxylase is rate-limiting in CMP-N-glycolylneuraminic acid (NeuGc) biosynthesis. These results, together with the previous observation that the level of CMP-NeuAc hydroxylase activity was associated with the expression of NeuGc in various tissues, support the notion that the enzyme is the key for regulation of the overall velocity of CMP-NeuAc hydroxylation and consequently for the expression of NeuGc-containing glycoconjugates.

The effect of sodium concentration on myocardial viability in donor heart preservation using a nondepolarizing solution

This study examined the effect of different sodium concentrations in a nondepolarizing solution on myocardial viability and functional recovery of the canine donor heart. Isolated canine hearts were preserved for 6 h at 5 degrees C, followed by normothermic reperfusion for 2 h. Dogs were divided into two groups of nine dogs each: group 1 received a nondepolarizing solution with 70 mM Na+ and group 2 with 30 mM Na+. The myocardial Ca2+ concentration at the end of preservation was significantly higher in group 1 than in group 2 and increased after reperfusion in both groups without any intergroup difference. Myocardial concentrations of ATP, ADP, and total adenine nucleotide at the end of reperfusion were significantly higher in group 1 than in group 2. Myocardial cyclic adenosine monophosphate concentration was significantly higher in group 1 than in group 2 at the end of both preservation and reperfusion. The myocardial cyclic guanosine monophosphate concentration in group 1 increased and was higher than in group 2 at the end of preservation, but had returned to normal levels by the end of reperfusion. However, it remained unchanged through preservation and reperfusion in group 2. The left ventricular systolic and diastolic function, assessed by pressure-volume relationship, was better in group 1 than in group 2. Mitochondrial ultrastructural changes were similar. These results suggest that a nondepolarizing solution containing 70 mM Na+ provides better myocardial protection than a solution containing 30 mM Na+.

Serial transcranial Doppler flow velocity and cerebral blood flow measurements for evaluation of cerebral vasospasm after subarachnoid hemorrhage

Serial transcranial Doppler (TCD) and cerebral blood flow (CBF) examinations were performed in 73 patients with subarachnoid hemorrhage (SAH) due to ruptured intracranial aneurysm to evaluate cerebral vasospasm. Twenty-six (35.6%) of the 73 patients developed ischemic neurological symptoms associated with cerebral vasospasm, which were reversible in all except four patients (5.5%) who demonstrated low-density areas associated with vasospasm on computed tomographic scans. In general, the flow velocities in the middle cerebral arteries began to increase soon after onset of SAH, reaching the maximum between days 8 and 10, subsequently decreasing gradually. There was no significant difference in the highest value and the time course of flow velocities between symptomatic vasospasm and asymptomatic vasospasm patients. Patients with symptomatic vasospasm demonstrated two typical time courses of flow velocities: rapid increases in flow velocities that preceded the clinical manifestations of vasospasm (16 patients, 61.5%), and no rapid increases in flow velocities despite the presence of ischemic symptoms (10 patients, 38.5%). In the latter, angiograms demonstrated vasospasm in segments distal to those evaluated by TCD examination. These results showed that the degree of cerebral vasospasm cannot be assessed only by the absolute flow velocities. CBF was measured two to 10 (mean 4.7) times within 3 weeks of SAH using the 133Xe intravenous injection method. The CBF value remained stable even during the period of major risk of vasospasm. However, the CBF was significantly lower in patients with symptomatic vasospasm on days 8, 9, 10, 13, 14, and 15, when compared with patients without symptomatic vasospasm.(ABSTRACT TRUNCATED AT 250 WORDS)

Reaction mechanism underlying CMP-N-acetylneuraminic acid hydroxylation in mouse liver: formation of a ternary complex of cytochrome b5, CMP-N-acetylneuraminic acid, and a hydroxylation enzyme

We have proposed that CMP-N-acetylneuraminic acid (CMP-NeuAc) hydroxylation is mediated by an electron transport system consisting of cytochrome b5 (b5), b5 reducing factor(s), and CMP-NeuAc hydroxylase, all of which have been detected in the cytosolic fraction of mouse liver [Kozutsumi, Y., Kawano, T., Yamakawa, T., & Suzuki, A. (1990) J. Biochem. 108, 704-706]. In order to elucidate the reaction mechanism underlying CMP-NeuAc hydroxylation, the interaction between b5 and the hydroxylase was studied using a b5-immobilized affinity column. The enzyme activity was retarded on the b5 column in the presence of the substrate, CMP-NeuAc, but not in the presence of the reaction product, CMP-N-glycolyneuraminic acid (CMP-NeuGc). These findings suggest that the binding of CMP-NeuAc to CMP-NeuAc hydroxylase changes the conformation of the enzyme so as to construct a recognition site for b5, followed by the formation of a ternary complex through this domain. Then the transport of electrons from NAD(P)H to the enzyme through b5 takes place, CMP-NeuAc is converted to CMP-NeuGc, and finally the ternary complex dissociates into its components to release CMP-NeuGc. It is known that a soluble form of b5 is abundant in erythrocytes and is synthesized from a mRNA different from that for the microsomal form of b5. In order to determine the origin of b5 detected in the cytosolic fraction of mouse liver, the molecular forms of b5 mRNA expressed in mouse liver were analyzed.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular organization at the glycoprotein-complex-binding site of dystrophin. Three dystrophin-associated proteins bind directly to the carboxy-terminal portion of dystrophin

Direct interaction between the C-terminal portion of dystrophin and dystrophin-associated proteins was investigated. The binding of dystrophin to each protein was reconstituted by overlaying bacterially expressed dystrophin fusion proteins onto the blot membranes to which dystrophin-associated proteins were transferred after separation by SDS/PAGE with the following results. (a) Among the components of the glycoprotein complex which links dystrophin to the sarcolemma, a 43-kDa dystrophin-associated glycoprotein binds directly to dystrophin. Although at least one of the binding sites of this protein resides within the cysteine-rich domain of dystrophin, a contribution of additional amino acid residues within the first half of the C-terminal domain was also suggested for more secure binding. (b) Two other proteins also directly bind to dystrophin. Their binding sites are suggested to reside within the last half of the C-terminal domain which is alternatively spliced depending on the tissue type. Previously, based on the enzyme digestion experiments, we showed that the binding site for the glycoprotein complex on dystrophin is present within the cysteine-rich domain and the first half of the C-terminal domain [Suzuki, A., Yoshida, M., Yamamoto, H. & Ozawa, E. (1992) FEBS Lett. 308, 154-160]. Here, we have extended this work and found that the region which is involved in interaction with the complex is widely extended to the entire length of this part of the molecule. On the basis of the present results, we propose a model of molecular architecture at the binding site for the complex on dystrophin.

Structure and expression of the gene for the prothoracicotropic hormone of the silkmoth Bombyx mori

We cloned and characterized two allelic variants of the gene for the Bombyx mori prothoracicotropic hormone (PTTH), a homodimeric 30-kDa brain secretory protein. These PTTH genes contain five exons that encode a precursor protein consisting of 224 amino acid residues whose C-terminal 109 residues represent the PTTH subunit. The Bombyx haploid genome contains a single copy of the PTTH gene. The major site of PTTH expression is the brain but expression at a very low level occurs in the gut. One Bombyx brain at day 0 of the fifth larval instar contained 2.4-2.8 pg PTTH mRNA, and this amount did not change markedly during larval-pupal development.

Autoinduction of activin genes in early Xenopus embryos

Activin exhibits a potent mesoderm inducing activity towards the ectodermal tissue (animal cap) of Xenopus laevis blastulae. Thus in order to investigate the role of activin in morphogenesis of early Xenopus embryos, activation of genes for activin beta A and beta B was examined by the reverse transcription polymerase chain reaction. In vivo, activin beta B mRNA appears to be present in embryonic stage 1 whereas beta A mRNA is undetectable prior to gastrulation. beta B and beta A mRNAs were noted to accumulate after stages 9 and 15 respectively. Activin gene expression in Xenopus animal caps was examined after treatment with various concentrations of activin A. Under these treatment conditions, both activin beta A and beta B mRNAs accumulated in a dose-dependent fashion after 24 h. The same effect was noted for treatment with similar concentrations of activin B. Accumulation of mRNAs was inhibited by the addition of cycloheximide to the culture medium, consistent with the proposition that activin gene expression requires certain protein factors. In total, therefore, these data suggest that an autoinduction mechanism is involved in the regulation of activin mRNA levels in normal Xenopus embryos and that this mechanism may play a pivotal role during early embryonic development.

Protective effects of kamikihi-to, a traditional Chinese medicine, against cerebral ischemia, hypoxia and anoxia in mice and gerbils

The protective effects of Kamikihi-To (KMK), a traditional Chinese medicine, against cerebral ischemia, hypoxia and anoxia were investigated with various experimental models in mice and gerbils. KMK (2.0 g/kg/day, p.o. for 5 days) significantly prolonged the survival time of mice subjected to bilateral common carotid artery occlusion. KMK (0.5 and 2.0 g/kg/day, p.o. for 5 days) also prolonged the survival time of mice injected with N-methyl-D-aspartic acid (NMDA: 80 mg/kg, i.v.). Furthermore, KMK (in a diet containing 8% KMK given orally for 34 days) showed protective effects against delayed neuronal death in CA1 pyramidal cells in the gerbil hippocampus after transient forebrain ischemia. On the other hand, we failed to show any protective effects of KMK (0.5-2.0 g/kg/day, p.o. for 5 days) against normobaric hypoxia and KCN-induced cytotoxic anoxia in mice. These results suggest that KMK may have protective effects against cerebral ischemic disorders, but not against severe hypoxic and anoxic disorders.