Preparation and activity of guanidinated or acetylated erabutoxins

1. Erabutoxins, a, b and c, neurotoxic proteins of a sea snake Lacticauda semifasciata, were guanidinated with O-methylisourea. The amino groups of all the lysine residues and those at the N-termini of the toxins were modified. The lethal activity of the toxins decreased to 50% (erabutoxins a and b) or 17% (erabutoxin c) of the original value on the modification. The c.d. (circular dichroism) maximum at 227 nm of the modified toxins became lower, whereas the whole profile of the c.d. curve remained unchanged. 2. The amino groups of erabutoxin b were acetylated with acetic anhydride. All the five monoacetyl derivatives were isolated from the reaction products by CM-cellulose and Bio-Rex 70 column chromatography. [1-Nalpha-acetylarginine]-, [15-N6-acetyl-lysine]- and [51-N6-acetyl-lysine]-erabutoxin b retained the toxicity of the native toxin, whereas [27-N6-acetyl-lysine] and [47-N6-acetyl-lysine]-erabutoxin b were 17 and 8% active respectively. The overall profile of c.d. spectrum of erabutoxin b remained unchanged on the monoacetylation.

[Effects of ATP on cerebral circulation--morphological observation of cerebral circulation and cerebral vasculature]

Review was made on the effect of adenosine triphosphate, 1.0-3.0 mg/kg intravenously, on the cerebral circulation and the presence of the dilating action on the cerebral blood-vessels in cats. 1. The group of the normal intra-cranial pressure showed, as reported previously, the transient hypotension and its complicated decrease of cerebral blood-circulation at the initial period for 30-100 check, then demonstrating the increase of cerebral blood-flow for 200-1000 check. Its increased volume and duration were dose-dependent. 2. The group of the loaded intracranial pressure of 20-30 mmHg (slightly elevated group) showed the increase of cerebral blood-flow, like the group of the normal intracranial pressure. However, the effect of ATP showed the decrease or disappearance in accordance with the elevation of the loaded pressure. 3. Cerebral vasodilating effect of ATP was promptly observed after the administration, and its degree was 30-50% in photographical observation. 4. Increasing effect on cerebral blood-flow and cerebral vasodilating action of ATP were similar in the pattern to that of vasodilators such as papaverine hydrochloride.

Evolution of 5sRNA

The evolution of 5sRNA of 17 organisms ranging from human to bacteria has been studied using a sequence homology analysis. The evolutionary rate of 5sRNA genes has been estimated to be 2.2x10(-10) replacement per one nucleotide site per year. This value is about the same as that of cytochrome C or tRNA's (congruent to 2x10(-10)). A phylogenic tree of these organisms including both eukaryotes and prokaryotes has been constructed from the evolutionary distances (the rate of nucleotide substitution per site) data. The time of divergence of prokaryotes and eukaryotes was estimated to be greater than or congruent to 1.75x10(9) years ago and the branching order in eukaryotic kingdoms is consistent with the traditional order. Blue-green algae separated from the bacterial stem greater than or congruent to 1.3x10(9) years ago after eukaryotes had branched.

[Effects of 1, 4-bis-(3-(3, 4, 5-trimethoxy benzoyl oxy)-propyl) perhydro-1, 4-diazepine (dilazep) on the isolated smooth muscles]

The effects of a new coronary vasodilator (dilazep) on isolated intestine, taenia coli, trachea, vas deferens, uter, aorta and coronary arteries were investigated in rats, guinea pigs, rabbits and dogs. Dilazep showed relaxant effects on isolated smooth muscle in a concentration of 10(-5) 3 X 10(-4) M and non-competitive inhibition on contraction induced by agonists (pD'2: 4.405.05). In guinea pig taenia coli, dilazep had a relaxant effect on K-contracture. The effect was qualitatively similar to that of papaverine. In guinea pig taenia coli, dilazep showed a Ca++ antagonistic effect in a concentration as high as 3 X 10(-6)M. The potency was stronger than dipyridamole, NaNO2 and aminophylline and equalled that of papaverine and hexobendine. In guinea pig taenia coli, dilazip potentiated relaxant effects induced by adenosine and adenine nucleotides in a concentration as high as 10(-8)M. The potency was stronger than that of dipyridamole. From these results, it is suggested that the potentiating effect of both adenosine and adenine nucleotides and Ca++ antagonistic effect of dilazep may play an important role in producing the coronary vasodilating effect.

[The effect of alphamethyltyrosine on cerebral vascular occlusive disease (author's transl)]

A double blind prospective study of the modification by alphamethyltyrosine (AMT) of experimental occulusion of the middle celebral artery (MCA) was performed on squirrel monkeys. The transorbital microsurgical technique was employed to expose the origin of the left MCA. A miniture Levis-Scoville clip was placed on the left MCA for 3 hours. Thirteen monkeys were given 10 ml/kg of 2% AMT solution approximately on hour prior to occlusion and just after revascularization. Thirteen control monkeys were given an equal volume of normal saline. After the removal of hte clip, detailed evaluation of neurological condition was recored every hour for 6 hours and at frequent intervals thereafter until the monkey expired or was sacrificed. The brain was perfused with biological carbon/saline solution and fixed glutaraldehyde using catheters placed in both common carotoid arteries. Brain samples were cut to 100 microns and examined with a light microscope. Immediately after the clip was placed on the MCA, all the animals demonstrated severe hemiparesis or hemiplegis of the contralateral side. When the clip was removed gradual recovery of function of the right side occured over a period of several hours. How,ever recovery was less complete in the control group, and even with seeming fair recovery of function in some animals, sudden death occured within 24 hours. Ten of the thirteen controls expired within 24 hours but only 2 AMT treated animals expired within 6 hours. Changes in blood pressure and gases due to AMT were negligible. In gross and microscopic examination, considerable brain edema with midline shift to the the contralateral side was observed in all untreated animals 6 hours after revascularization. Leakage of carbon, indicating microvasculature damage, occured in the infarcted areas and in the surrounding tissues. The sam degree of brain edema and infarction was observed in the AMT treated animals which were died within 6 hours after revascularization. Better perfusion with carbon black and less edema were, however, seen in other AMT treated animals 6 afters after revacularization...

Experimental inhibition of serotonin by antibiotic: prevention of cerebral vasospasm

✓ Cerebral arterial spasm was induced in four groups of monkeys by transorbital puncture of the middle cerebral artery. Oral administration of kanamycin was found to inhibit the spasm, and reserpine also interfered with its development. Desoxypyridoxine, a pyridoxine antagonist, did not. Protection from vasospasm occurred only when blood serotonin levels were reduced more than 75%.

Analysis of the principal g-tensors in single crystals of ferrimyoglobin complexes

This paper describes a method of determining the directions of the principal axes of the g-tensors in single crystals from measurements of the g-value variation in three crystalline planes (ab, bc*, ac) and of the principal values of g-tensors. Measurements of paramagnetic resonance spectra of ferrimyoglobin (Mb(Fe3+)) complexes (Mb(Fe3+).CN-, .N3-, .imidazole(Im.) and .OCN-) in single crystals provided detailed information on the electronic state of the Fe3+. The direction of the z axis in Mb(Fe3+).CN-, .N3- and .Im. is not parallel to that in Mb(Fe3+).H2O, which has been used as the haem normal, where the z axis is one of the principal axes of the g-tensors corresponding to the maximal (in low-spin state of Fe3+ in haem) or minimal (in high-spin state of Fe3+ in haem) g-value. In Mb(Fe3+).OCN-, however, which is in thermal equilibrium between high-spin and low-spin states, the directions of the z axis in both states seem to be perpendicular to the haem plane. The direction of the x axis is not parallel to the plane of the linked histidine ring.