Functional expression of cloned cDNA encoding the alpha-subunit of adenylate cyclase-stimulating G-protein

Cloned cDNA encoding the alpha-subunit of the adenylate cyclase-stimulating G-protein (Gs), carried by a simian virus 40 vector, has been introduced into the cyc- variant of S49 lymphoma cells by electroporation. In contrast to untransfected cys- cells, clones transformed with the cDNA exhibit an increase in intracellular cyclic AMP concentration in response to a beta-adrenergic agonist.

Synthesis of a heptasaccharide hapten related to a biantennary glycan chain of human chorionic gonadotropin of a choriocarcinoma patient. A convergent approach

Synthesis of the heptasaccharide hapten 8-methoxycarbonyloctyl O-beta-D-galactopyranosyl-(1----4)-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----2)-O-[beta-D-galactopyranosyl-(1----4)-O-(2-acetam ido-2- deoxy-beta-D-glucopyranosyl)-(1----4)]-O-alpha-D-mannopyranosyl-(1----3) -O- [alpha-D-mannopyranosyl-(1----6)]-beta-D-mannopyranoside is described, by use of the known, protected glycosyl acceptor 8-ethoxy-carbonyloctyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-mannopyranosyl)-(1----6)-2,4-di-O-benz yl-beta - D-mannopyranoside, and the key glycopentaosyl donors O-(2,3,4,6-tetra-O-acetyl-beta-D-galactopyranosyl)-(1----4)-O-(2-acetami do-3,6- di-O-acetyl-2-deoxy-beta-D-glucopyranosyl)-(1----2)-O-[(2,3,4,6-tetra-O- acetyl-beta-D-galactopyranosyl)-(1----4)-O-(2-acetamido-3,6-di-O-acetyl- 2- deoxy-beta-D-glucopyranosyl)-(1----4)]-3,6-di-O-benzyl-alpha-D-mannopyra nosyl trichloroacetimidate (5) and the corresponding fluoride 7, which, in turn, were prepared in 5 steps from allyl 3,6-di-O-benzyl-alpha-D-mannopyranoside in 35 and 22% overall yields, respectively. In model experiments, the key glycosyl donors 5 and 7 were also treated with the simple glycosyl acceptor 8-ethoxycarbonyloctanol, to give 8-methoxycarbonyloctyl O-beta-D-galactopyranosyl-(1----4)-O-(2-acetamido-2-deoxy-beta-D- glucopyranosyl)-(1----2)-O-[beta-D-galactopyranosyl-(1----4)-O-(2-acetam ido-2- deoxy-beta-D-glucopyranosyl)-(1----4)]-alpha (and beta)-D-mannopyranoside.

Synthesis of a heptasaccharide hapten related to an anomalous biantennary glycan-chain of human chorionic gonadotropin of a patient with choriocarcinoma. A stepwise approach

A stereocontrolled synthesis of a heptasaccharide hapten, 8-methoxycarbonyloctyl 3-O-[2,4-di-O-(2-acetamido-2-deoxy-4-O-beta-D-galactopyranosyl-beta-D- glucopyranosyl)-alpha-D-mannopyranosyl]-6-O-alpha-D-mannopyranosyl-beta- D-mannopyranoside (2), is described employing the lactosaminyl donor 3,6-di-O-acetyl-2-deoxy-2-phthalimido-4-O-(2,3,4, 6-tetra-O-acetyl-beta-D-galactopyranosyl)-beta-D-glucopyranosyl bromide and the mannotriosyl glycosyl acceptor 8-ethoxycarbonyloctyl 2,4-di-O-benzyl-3-O-(3,6-di-O-benzyl-alpha-D-mannopyranosyl)-6-O-(2,3, 4,6-tetra-O-benzyl-alpha-D-mannopyranosyl)-beta-D-mannopyranoside, the reaction of which gave the biantennary structure 8-ethoxycarbonyloctyl 2,4-di-O-benzyl-3-O-(3,6- di-O-benzyl-2,4-di-O-[3,6-di-O-acetyl-2-deoxy-2-phthalimido-4-O-(2,3, 4,6-tetra-O-benzyl-alpha-D-mannopyranosyl)-beta-D-mannopyranoside (9), as well as a monoglycosylated product, 8-ethoxycarbonyloctyl 2,4-di-O-benzyl-3-O-(3,6-di-O-benzyl-4-O-[3,6- di-O-acetyl-2-deoxy-2-phthalimido-4-O-(2,3,4,6- tetra-O-benzyl-alpha-D-mannopyranosyl)-beta-D-mannopyranoside. The diglycosylated product 9 was transformed into 2, and the structure was confirmed by 1H-n.m.r. data.

Primary structure of the alpha-subunit of bovine adenylate cyclase-inhibiting G-protein deduced from the cDNA sequence

The primary structure of the alpha-subunit of the adenylate cyclase-inhibiting G-protein (Gi) has been deduced from the nucleotide sequence of cloned DNA complementary to the bovine cerebral mRNA encoding the polypeptide. A much higher degree of amino acid sequence homology is observed between the alpha-subunits of Gi and transducin (68%) than between those of Gi and the adenylate cyclase-stimulating G-protein (Gs) (43%) or between those of transducin and Gs (42%).

Primary structure of the alpha-subunit of bovine adenylate cyclase-stimulating G-protein deduced from the cDNA sequence

The primary structure of the alpha-subunit of the adenylate cyclase-stimulating G-protein (Gs) has been deduced from the nucleotide sequence of cloned DNA complementary to the bovine cerebral mRNA encoding the polypeptide. Comparison of the amino acid sequences of the alpha-subunits of Gs and transducin reveals that some of the highly conserved regions show sequence homology with elongation factor-Tu and ras p21 proteins and correspond to functional regions of guanine nucleotide-binding proteins.

Primary structure of the beta-subunit of bovine transducin deduced from the cDNA sequence

DNA complementary to the bovine retinal mRNA coding for the beta-subunit of transducin has been cloned by screening a cDNA library with oligodeoxyribonucleotide probes. Nucleotide sequence analysis of the cloned cDNA has revealed that this polypeptide consists of 340 amino acid residues (including the initiating methionine). Furthermore, cDNA hybridizable with a transducin beta-subunit cDNA probe has been cloned from a library derived from bovine brain poly(A)+ RNA. Comparison of the cloned cDNAs, in conjunction with blot hybridization analysis and S1 nuclease mapping of poly(A)+ RNA from bovine retina, brain and liver, suggests that the mRNAs coding for the beta-subunits of transducin and other guanine nucleotide binding proteins have the same protein-coding sequence but partly different 5'-noncoding sequences.

Primary structure of the alpha-subunit of transducin and its relationship to ras proteins

A group of membrane-associated guanine nucleotide binding proteins (G-proteins) are essential for transducing signals generated at cell-surface receptors into changes in cellular function and metabolism. These proteins are a complex of three subunits designated alpha, beta and gamma. The alpha-subunit is responsible for binding guanine nucleotides and seems to be characteristic of each protein. Transducin, a member of this protein family, mediates visual transduction by coupling the signal of photolysed rhodopsin with activation of a cyclic GMP phosphodiesterase. We have now cloned and sequenced the complementary DNA encoding the alpha-subunit of bovine retinal transducin and from this we have deduced the complete amino-acid sequence. The transducin alpha-subunit shares several homologous amino-acid sequences with ras gene products. The homologous segments correspond mostly to the regions thought to be involved in the guanine nucleotide binding and GTPase activity of ras proteins and to the ADP-ribosylation sites of the transducin alpha-subunit.

Muscarinic receptors in porcine caudate nucleus. II. Different effects of N-ethylmaleimide on [3H]cis-methyldioxolane binding to heat-labile (guanyl nucleotide-sensitive) sites and heat-stable (guanyl nucleotide-insensitive) sites

Heat treatment of membranes from porcine caudate nucleus (50 degrees for 7 min) caused a marked decrease in [3H]cis-methyldioxolane [( 3H]CD) binding without affecting seriously the binding of [3H]3-quinuclidinyl benzilate [( 3H]QNB). Approximately 20% of the [3H]CD binding at 5 nM [3H]CD remained after the heat treatment. The remaining binding was not affected by 0.1 mM guanylyl-5'-imidodiphosphate (GppNHp) or by nickel or other cations at concentrations below 10 mM. Treatment of the membranes with trypsin (30 micrograms/mg of protein) at 20 degrees for 20 min also caused a marked decrease in [3H]CD binding without affecting seriously the binding of [3H]QNB. About 20% of the original [3H]CD binding remained in the presence of trypsin at a high concentration of protein (90 micrograms/mg). N-Ethylmaleimide (NEM) affected [3H]CD binding in two different ways: (a) preincubation of the membranes with NEM caused a marked reduction in heat- and GppNHp-sensitive [3H]CD binding, and (b) treatment with NEM caused an enhancement of heat-, GppNHp-, and trypsin-insensitive [3H]CD binding. Neither of the NEM effects required the coexistence of agonists. The concentration of NEM required for the first effect was 10 times lower than that for the second effect, indicating the existence of two NEM-binding sites with different affinities for NEM. The equilibrium dissociation constant (Kd) for [3H]CD after NEM treatment was 33 nM and was not affected by GppNHp, Ni2+, or heat treatment; the Kd was only 4 times higher than that (8 nM) without NEM treatment. These findings indicated the existence of two kinds of [3H]CD binding sites with high affinities for agonists: one is sensitive to guanyl nucleotide and is abolished by NEM and the other is induced by NEM and insensitive to guanyl nucleotide.

Muscarinic receptors in porcine caudate nucleus. I. Enhancement by nickel and other cations of [3H]cis-methyldioxolane binding to guanyl nucleotide-sensitive sites

Muscarinic acetylcholine receptors in the synaptic membrane fraction of porcine caudate nucleus were characterized by using a radiolabeled agonist, [3H]cis-methyldioxolane [( 3H]CD) and an antagonist, [3H]quinuclidinyl benzilate [( 3H]QNB). Scatchard analysis of the specific binding of [3H]CD gave a single equilibrium dissociation constant of 8.1 nM when a concentration of less than 80 nM [3H]CD was used. The binding capacity was 390 fmoles/mg of protein and corresponded to about 10% of the binding sites of [3H]QNB. Agonist/[3H]CD competition binding experiments indicated that [3H]CD was selectively bound to the sites with a high affinity for agonists. [3H]CD binding was inhibited by Na+, K+, Mg2+, and Ca2+ with the half-maximal effect at 10-50 mM. Nickel ion showed biphasic effects on [3H]CD binding: a 2- to 3-fold enhancement of binding at 0.1-10 mM and inhibition above 10 mM. Other cations, including Co2+, Mn2+, and Zn2+, at 1 mM also increased [3H]CD binding by a factor of 1.5-1.8. Among 18 cations examined, only Cd2+, Hg2+, and Cu2+ caused significant inhibition of [3H]CD binding at 1 mM. [3H]CD binding was decreased to about 20% of the control value in the presence of guanylyl-5'-imidodiphosphate (GppNHp), GTP, and GDP with the half-maximal effect at 1.3, 32, and 45 microM, respectively. [3H]CD binding in the presence of Ni2+ was decreased by GppNHp to a level obtained in the presence of GppNHp alone. The increase caused by Ni2+ in [3H]CD binding was due to the increase in the maximal binding capacity (Bmax) without changes in the affinity for [3H]CD. We conclude that Ni2+ increases the proportion of a muscarinic receptor subclass (or state) that is sensitive to guanyl nucleotide.

Myoclonus in a case of suspected progressive rubella panencephalitis

Predominantly unilateral myoclonus induced by movement of the affected parts in a 21-year-old Japanese man with suspected progressive rubella panencephalitis appeared in the course of treatment for epilepsy with anticonvulsant drugs after five years. Antirubella antibody levels in the serum and CSF were elevated and IgM antibody against rubella was found in the serum. An EEG recorded while the patient was awake showed diffuse 3- to 4-Hz theta activity with high voltage. The neurological symptoms are progressing slowly.

The use of labetalol in Japan: results of multicentre clinical trials

1 The anti-hypertensive effects and safety of labetalol have been evaluated in multicentre clinical trials in Japan based on unified study protocols. The results of three studies are reported. 2 A total of 178 patients with essential hypertension were treated with labetalol for 12 weeks, 127 of them with labetalol alone (monotherapy) and the other 51 with labetalol plus diuretics (combined therapy). 3 Satisfactory antihypertensive effects were achieved in 76 of the 119 assessable patients in the monotherapy group and 25 of the 49 in the combined therapy group. The mean daily doses of labetalol were 329 mg in the monotherapy group and 374 mg in the combined therapy group. Seven patients (six in the monotherapy group; one in the combined therapy group) were withdrawn from the trials due to side-effects. 4 Sixty-one patients with hypertension were treated with labetalol alone or combined with diuretics for 6 months or longer. In most of these patients, good blood pressure control was achieved. No patients had to discontinue the treatment due to side-effects. The mean daily doses of labetalol were stabilised in and after week 8 of the treatment at an average of 260 mg in the monotherapy and 450 mg in the combined therapy. Tolerance to the anti-hypertensive effect did not develop. 5 Thirty patients with phaeochromocytoma were treated with labetalol and good blood pressure control was achieved in 21 of them. The effects of labetalol were better in patients with predominantly adrenaline-secreting tumours, and better in patients with sustained hypertensive type than in those with paroxysmal hypertensive type.

Ultrasonic evaluation of superficial temporal artery-middle cerebral artery anastomosis

Ultrasonic Doppler studies were made pre- and postoperatively in 22 patients undergoing STA-MCA anastomosis. A quantitative evaluation of the bypass was attempted by determining the STA blood flow velocity and pattern. The STA velocity on the Doppler sonogram was compared with the degree of intracranial vascular filling via anastomotic channels and the STA diameter on angiogram. The STA velocity was increased and the blood flow pattern of STA altered from an external carotid pattern to an internal carotid pattern in a patent bypass. The results were in good agreement with angiographic findings. The are of intracranial vascular filling via a vewly formed bypass on angiogram was proportional to the increase in STA velocity. As the STA diameter enlarged, the STA velocity increased progressively. It is suggested the Doppler flowmetry is reliable as a semi-quantitative means of evaluationg the STA-MCA anastomosis.

Internal carotid occlusion: assessment, by Tc-99m-tagged microspheres, of bypass from superficial temporal to middle cerebral artery

The assessment of regional blood perfusion through the STA-MCA anastomosis was performed by the method of intracarotid injection of Tc-99m-labeled human albumin microspheres (HAM scintigraphy). This study included 11 anastomoses in 10 cases with occlusion of the internal carotid artery, who were treated by bypass surgery. The area of intracranial perfusion through the bypass was well defined in all cases by HAM scintigraphy. This method is excellent for imaging the regional blood perfusion through the anastomotic vessel, and the scintigraphic findings agree well with those of postoperative angiography. HAM scintigraphy will partially replace postoperative angiography because of its simplicity and low invasiveness.

Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part I. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and angiogram

In 24 patients with cerebrovascular disease and 6 without organic brain lesions, the increased velocity of blood flow in both the internal carotid and vertebral arteries during a contralateral carotid compression was compared with the angiographic appearance of the circle of Willis. The flow velocity was measured using ultrasonic Doppler flowmetry. It was not possible to investigate fully the relationship between the increase of velocity of blood flow in the internal carotid artery and the anatomical variations of the circle of Willis, specifically the anterior cerebral and communicating arteries. The velocity of flow in the patients with an aplastic proximal portion of the anterior cerebral artery showed no increase. There were no differences in the increase of velocity of flow in the vertebral artery in patients with hypoplastic, normal and fetal posterior communicating arteries. It is considered that although anatomical variations of the circle vessels influence the cross-circulation via the circle of Willis, peripheral vascular factors distal to the circle also play an important role in the quantity of cross-circulation through the circle.

Evaluation of cross-circulation through circle of Willis using an ultrasonic Doppler technique. Part II. Comparison between blood flow velocity by ultrasonic Doppler flowmetry and cerebrovascular resistance

The correlation between the increase in velocity of blood flow in both the internal carotid and vertebral arteries during a carotid compression and the cerebrovascular resistance (CVR) was investigated in 11 patients with chronic ischemic cerebrovascular disease and 4 without organic brain lesions. The velocity of blood flow was measured by an ultrasonic Doppler flowmeter. CVR was calculated from cerebral blood flow and arterial blood pressure. There was no correlation between the increased velocity of blood flow in the internal carotid and vertebral arteries and CVR. The increased velocity of blood flow in patients with low CVR was, however, significantly higher than that of patients with high CVR. The investigation of cross-circulation by ultrasonic Doppler flowmetry is a useful non-invasive method for the detection of changes in cerebral vascular resistance.

Ultrasonic Doppler studies after superficial temporal-middle cerebral artery anastomosis

The ultrasonic Doppler technique was applied to evaluate the effect of STA-MCA anastomosis. Not only the STA itself, but also ophthalmic and major aortocranial arteries were recorded by the Doppler technique in 12 patients who had undergone STA-MCA anastomosis for internal carotid artery occlusion or stenosis. The examination was performed before, and within a month after the operation. The blood flow pattern of the STA, which had had an external carotid flow pattern, was altered to an internal carotid flow pattern by the STA-MCA bypass operation. The findings of Doppler sonograms of the STA were exactly consistent with post-operative angiograms and precisely represented the bypass patency. Among 7 patients with reverse flow direction in the ophthalmic artery before the operation, the reverse flow had decreased in 5 patients post-operatively. But no remarkable change in the ophthalmic artery was detected in the remaining 2 patients. The blood flow velocity patterns of major aortocranial arteries showed no change post-operatively.

Hemodynamic and volume characteristics, and peripheral plasma renin activity in Takayasu's arteritis

Hemodynamic and volume characteristics, and/or peripheral plasma renin activity were investigated in 19 patients with Takayasu's arteritis who included 8 hypertensive patients with renal arterial disease and 11 normotensive patients. In hypertensive patients, mean arterial pressure had an inverse correlation with cardiac index, a direct correlation with total peripheral resistance index and no correlation with blood volume. These hemodynamic and volume characteristics were different from those of hypertension with renal arterial disease previously reported. High plasma renin activity was presented in not only hypertensive patients with renal arterial disease but normotensive patients. The investigation of high plasma renin activity in Takayasu's arteritis must be also directed to the mechanism except renal arterial lesions.