Synthesis of mu-conotoxin GIIIA: a chemical probe for sodium channels

mu-Conotoxin GIIIA, a 22 amino acid peptide paralytic toxin which inhibits the muscle voltage-activated sodium channels, was synthesized by a solid phase method. No purification of intermediates was necessary for the synthesis, and a simple air oxidation of the deprotected crude peptide gave the desired toxin. By all criteria applied, the synthetic material was indistinguishable from the authentic natural toxin.

[Angiographic positions for thoracic outlet syndrome]

Thirty four patients (18 males and 16 females, 54 lesions) with thoracic outlet syndrome (TOS) were studied with conventional angiography. Angiography in the supine position did not confirm subclavian artery compression in 43.4% of patients. Lordotic position or upright position was useful for demonstration of subclavian artery compression in patients who did not show any findings in conventional techniques.

Boar acrosin digestion of the porcine egg coat, zona pellucida, and rearrangement of the zona proteins

Mechanically isolated, structurally intact porcine zonae pellucidae composed of three families of glycoproteins (PZP1-3) were digested with purified boar acrosin, and then the solublized and unsolubilized fractions were separately analyzed by HPLC and/or SDS-PAGE. In isotonic solution, PZP1 was first degraded and then PZP2, whereas PZP3 was quite resistant to acrosin, reflecting the organization of these families in the zona structure. As the proteolytic hydrolysis proceeded, high-molecular-weight products appeared in the unsolubilized fraction. These products disintegrated on treatment with beta-mercapto-ethanol. The zona materials solubilized by acrosin were separated into seven fractions by reverse phase HPLC. The total yield of the latter was only about 5% by weight. Thus, limited sites of the porcine zona were cleaved by the homologous sperm acrosin. Since five fractions contained peptides that were more hydrophilic than the original proteins, these peptides seemed likely to be present on the outer surface of the zona structure. SDS-PAGE of the unsolubilized fraction showed that acrosin cleaved the zona at many more sites in hypotonic solution than in isotonic solution. Thus, structural relaxation of the inner region of the zona was indicated to be induced under hypotonic conditions. However, no high-molecular-weight products were formed in hypotonic solution, suggesting that the native architecture of the zona is a prerequisite for their formation.

Modification of porcine zona pellucida with fluorescein isothiocyanate: evidence for the presence of a structural unit consisting of glycoproteins in the mammalian egg coat

Intact porcine ova and mechanically isolated zonae pellucidae from the ova were treated with a limiting amount of FITC in isotonic solutions at different pHs. The modified zona proteins were fractionated into three families (FTC-PZP1-3) by HPLC on a gel filtration column. It was found by this HPLC that the amino groups of PZP3 hardly reacted with FITC, whereas those of PZP1 and 2 fairly reacted, reflecting the organization of these families in the zona structure. The difference in reactivity of the three families with FITC suggested the presence of a structural unit in the zona, thus supporting the filamentous model of Wassarman.

[A quantitative measurement of the cerebral infarct focus induced by arachidonate infusion and the relationship between measured values and stroke signs]

A method for measuring the organic infarct focus induced by arachidonate infusion into rat brain was devised, and the statistical relationship between the measured values and stroke signs in the rat was studied. By the infusion of arachidonate, a high incidence of cerebral infarction was found in the live rats with uniformly necrotized foci. The size of these foci (infarction rate) were measured by transcripting them to a graduated brain sheet. The relationship between the independent parameter of the infarction rate and the dependent parameter of stroke signs was fully analyzed by multidimensional quantification. Many animals showed no stroke signs despite having lesions (false negative). By contract, no animal without any lesion showed stroke signs (false positive). When each parameter of these signs were quantified and normalized, the stumbling and abnormal posture signs showed a wide range of values, relatively accurately reflecting the infarction degree. Moreover, the highest partial correlation ratio between the various parameters was found to be that between the stumbling and abnormal posture stroke signs. Thus, it may be said that the stumbling and the abnormal posture stroke signs can be considered relatively good parameters for evaluating the degree of an infarction. These parameters should be useful for the testing of anti-infarction drugs.

[An analysis of the morbid condition in adjuvant arthritic rats and a new method for evaluating anti-rheumatic drugs]

The progress of various symptoms in adjuvant arthritic rats (AA-rats) and the effects of anti-rheumatic drugs were continuously observed on the basis of the Weibull distribution function, and the following results were obtained: 1) The cumulative incidence rates F(t) of various symptoms and abnormalities of measured values gradually increased with the passage of time. The relationship between the F(t) and the days after adjuvant injection indicated a simple Weibull distribution function. On the other hand, the bone damages in the distal limb joints indicated a composite Weibull distribution function with two shape parameters (m1 and m2). It was possible to classify the animals into two groups, fast responders (m1) and slow responders (m2), according to the time of occurrence of bone damages. 2) By using the Weibull probability paper, it was possible to integrate and to evaluate in totality those cases with varying grades of symptoms and cases with different symptoms in the adjuvant-induced syndrome in rats. 3) Azathioprine (AZP) showed an inhibitory effect on the advents of pain and swelling and functional disorders, while indomethacin (IDM), prednisolone (PSL) and gold sodium thiomalate (GST) delayed the advents of these symptoms. As to bone damages in the distal limb joints, IDM, PSL and AZP showed an inhibitory effect in only the fast responder group, while GST showed both an inhibitory and delaying effect in both the fast responder group and the slow one. The above results suggest that the usage of the Weibull distribution function is useful not only for analysis of the morbid condition of AA-rats but also for the evaluation of anti-rheumatic drugs in AA-rats.

Radiotherapy of spontaneous carotid-cavernous sinus fistulas

Between 1984 and 1986, 7 patients with spontaneous carotid-cavernous fistulas (CCF) were treated by radiotherapy delivering 3,000 cGy (200 cGy, 5 times per week) to the sellar region. Improvements of clinical signs and symptoms were seen in all patients within 6 months of treatment. During a follow-up period of 7 to 35 months, 6 patients remained in good clinical condition and only one patient developed a recurrence. As an adverse effect, one patient developed early menopause, but no other side-effects or complications were seen. Radiotherapy should be considered in patients with spontaneous CCF, when CCF are seen in middle-high aged patients and progressive without relief of symptoms.

Solubilization of porcine zonae pellucidae by trypsin and pronase

The porcine zona pellucida was dissolved with difficulty by trypsin in isotonic solution, whereas it was efficiently dissolved by pronase. A structural change of the zona was induced in hypotonic solution, resulting in acceleration of dissolution by these proteases. The solubilization rate of three families (PZP1-3) of zona protein by both enzymes was analyzed by HPLC. In hypotonic solution, PZP1 was solubilized first, followed by PZP2; and PZP3 was then finally released. In isotonic solution, PZP1 and PZP2 were also solubilized faster than PZP3, which was almost completely resistant to trypsin, showing that the solubilization of the zona depended on that of PZP3. Noticeably, high molecular weight products were produced as the proteolytic hydrolysis proceeded in PBS. Circular dichroic spectra and electrophoretograms of the tryptic hydrolysates showed that the zona may have a regular supramolecular structure.

Fractionation of glycoproteins from porcine zonae pellucidae into three families by high-performance liquid chromatography

The glycoproteins of porcine zonae pellucidae were fractionated into three families (PZP1-3) by high-performance liquid chromatography on a gel filtration column. Their molecular weights were estimated to be 164K for PZP1, 99K for PZP2, and 55K for PZP3; and they were present in an approximate weight ratio of protein moiety of 2:3:18, respectively. Differences in carbohydrate composition position between them were found, although their amino acid compositions were similar to each other. CD spectra showed that the three families had an almost identical secondary structure of the helical form in the presence of SDS. In PBS without SDS, they had different secondary structures, predominantly in the beta-form, and probably different tertiary structures.

Interactions of derivatives of guanidinophenylalanine and guanidinophenylglycine with Streptomyces griseus trypsin

The rates of hydrolysis of the ester, amide and anilide substrates of p-guanidino-L-phenylalanine (GPA) by Streptomyces griseus trypsin (S. griseus trypsin) were compared with those of arginine (Arg) substrates. The specificity constant (kcat/km) for the hydrolysis of GPA substrates by the enzyme was 2-3-times lower than that for arginine substrates. The kcat and Km values for the hydrolysis of N alpha-benzoyl-p-guanidino-L-phenylalanine ethyl ester (Bz-GPA-OEt) by S. griseus trypsin are in the same order of magnitude as those of N alpha-benzoyl-L-arginine ethyl ester (Bz-Arg-OEt), although both values for the former when hydrolyzed by bovine trypsin are higher by one order of magnitude than those for the latter. The specificity constant for the hydrolysis of Bz-GPA-OEt by S. griseus trypsin is much higher than that for N alpha-benzoyl-p-guanidino-L-phenylglycine ethyl ester (Bz-GPG-OEt). As with the kinetic behavior of bovine trypsin, low values in Km and kcat were observed for the hydrolysis of amide and anilide substrates of GPA by S. griseus trypsin compared with those of arginine substrates. The rates of hydrolysis of GPA and arginine substrates by S. griseus trypsin are about 2- to 62-times higher than those obtained by bovine trypsin. Substrate activation was observed with S. griseus trypsin in the hydrolysis of Bz-GPA-OEt as well as Bz-Arg-OEt, whereas substrate inhibition was observed in three kinds of N alpha-protected anilide substrates of GPA and arginine. In contrast, no activation by the amide substrate of GPA could be detected with this enzyme.

A new beta-naphthylamide substrate of p-guanidino-L-phenylalanine for trypsin and related enzymes

N alpha-Benzyloxycarbonyl-p-guanidino-L-phenylalanine beta-naphthylamide (Z-GPA-beta NA) was synthesized and the susceptibility of this compound to trypsin and related enzymes was compared with that of N alpha-benzyloxycarbonyl-L-arginine beta-naphthylamide (Z-Arg-beta NA). Both Z-GPA-beta NA and Z-Arg-beta NA were rapidly and almost completely hydrolyzed by trypsin and pronase. Z-Arg-beta NA was hydrolyzed slowly by thrombin, while Z-GPA-beta NA was not susceptible to this enzyme at all. The rate of hydrolysis of Z-GPA-beta NA by papain was slower than that of Z-Arg-beta NA. Neither beta-naphthylamide substrate was hydrolyzed by alpha-chymotrypsin. The specificity constant (kcat/Km) for the hydrolysis of Z-GPA-beta NA by trypsin was somewhat larger than that for the hydrolysis of Z-Arg-beta NA. Contributions of the benzene ring in the side chain of Z-GPA-beta NA to good binding of this substrate to the specificity site of this enzyme and to the poor fit of the scissile bond in the substrate molecule to the active serine residue are presumed from comparison of the individual kinetic parameters (Km and kcat) for the two beta-naphthylamide substrates. Z-GPA-beta NA was ascertained to be a useful substrate in the study of the binding and catalytic specificities of various trypsin-like enzymes.

[Pharmacological actions of iprazochrome on the vascular system]

The pharmacological actions of iprazochrome (IC) on the vascular system were studied, and the following results were obtained: No death nor abnormal behaviors were observed in acute toxicity tests conducted on male and female mice and rats despite the administration of large doses of IC (10,000 mg/kg, p.o. and 80 mg/kg, i.v., respectively). IC inhibited dose-dependently platelet aggregation in vitro induced by arachidonate and ADP, whereas no effect was observed on ADP-induced respiratory depression in mice, which is closely related to platelet aggregation in vivo. The antiserotonergic actions of IC on the isolated external carotid arteries and femoral arteries in dogs observed in a noncompetitive manner were found to be 1/24 to 1/65 that of methysergide. On the other hand, IC showed no inhibitory effect on the paw edema of rats in vivo induced by serotonin. The inhibitory effect of IC on peritoneal dye leakage in mice was less than half that of phenylbutazone. IC prevented apoplexy in stroke-prone SHR (SHRSP) without lowering the blood pressure. Histological changes in the cerebrum of SHRSP were ischemic changes such as swelling of the neurons and shrinkage of the nuclei, mainly in the cerebral cortex and corpus striatum area.

Hydrolysis of phenylthiazolones of p-guanidinophenylalanine and arginine by trypsin and related enzymes

The phenylthiazolone (PTA) of p-guanidinophenylalanine (GPA) was synthesized and the susceptibility of this compound to trypsin and related enzymes was compared with that of the PTA of arginine (Arg). Both PTA-GPA and PTA-Arg were almost completely and rapidly hydrolyzed by trypsin and pronase. PTA-Arg was hydrolyzed rapidly by thrombin, whereas PTA-GPA was less susceptible to this enzyme. The rates of hydrolysis of the two PTAs by alpha-chymotrypsin and papain were fairly slow. The specificity constant (kcat/Km) for the hydrolysis of PTA-GPA by trypsin was about 4 times larger than that of PTA-Arg. Thus, PTA-GPA, as well as PTA-Arg, behaves as a specific internal thioester substrate for trypsin and is the best one in the series of PTA substrates examined so far. However, PTA derivatives of GPA and Arg were hydrolyzed with kcat/Km values smaller than those of N alpha-benzoyl ethyl esters of L-GPA and L-Arg by factors of 4 and 17, respectively.

[Effects of dihydroergotamine mesylate (DEM) on the cardiovascular and nervous systems (author's transl)]

Effects of DEM on the cardiovascular, autonomic, and central nervous systems were studied using dogs, rats and rabbits. DEM showed relatively weak effects on the EEG in curarized rabbits and on ambulatory and drinking activities in rats. DEM suppressed dose-dependently the pressor responses induced by norepinephrine, serotonin and bilateral carotid occlusion, but had no effect on the depressor responses induced by acetylcholine and electrical stimulation to the postganglionic vagus nerve in anesthetized dogs. DEM produced a dose-dependent increase in blood pressure, a dose-dependent decrease in heart rate, a transient decrease in respiration rate, and little change in the ECG of anesthetized dogs. The pressor responses induced by DEM were inhibited by phentolamine, methysergide, and indomethacin in anesthetized dogs. With canine femoral arteries, DEM-induced contractions were blocked 10% by phentolamine, 60% by methysergide, and enhanced 10% by indomethacin. On the other hand, DEM-induced contractions of the femoral veins were blocked 30% by phentolamine, 60% by indomethacin, and 10% by methysergide. DEM provoked a significant increase in the level of prostaglandin E in the bathing fluid of the veins but not in that of the arteries. The results suggest that the arterioconstrictor responses induced by DEM are mediated mainly through the serotonin receptors, and the venoconstrictor responses induced by DEM mainly through the enhanced synthesis of prostaglandin E.

[Comparative responsiveness of isolated saphenous, femoral and external carotid arteries and veins of dogs to dihydroergotamine mesylate (DEM) (author's transl)]

Changes in tension of spiral strips of saphenous, femoral and external carotid arteries and veins were measured isometrically. DEM stimulated 6 preparations in almost the same concentration ranges (pD2 values were 8.64 to 8.40). However, the dose-response curves for DEM indicted variations in responsiveness among the different arteries and veins. Compared with norepinephrine (NE) (1)( the intrinsic activity of DEM was 0.002 on saphenous arteries, 0.05 on saphenous veins, 0.03 on femoral arteries, 0.18 on femoral veins, 0.13 on external carotid arteries and 0.13 on external carotid jugular veins. Thus DEM contracted more potently the venous strips from the hind limbs. IN femoral and external carotid arteries, antagonism of serotonin by DEM or methysergide was investigated. DEM displaced the dose-contractile response curves for serotonin in a noncompetitive manner, and the antagonistic response of DEM to serotonin was about 8 times more effective in external carotid arteries (pD'2 value=6.96) than in femoral arteries (pD'2 value=6.05). Methysergide, unlike DEM, antagonized the response to serotonin in a competitive manner at low doses but in a noncompetitive manner in high doses, and was fairly equal in antagonizing response to serotonin in external carotid arteries (pA2 value=that the therapeutic value of DEM in the treatment of orthostatic hypotension is due to its selective anti-serotonin activity on the external carotid arteries.

A method for evaluating analgesic agents in rats

A method is described for evaluating antinociceptive activity in rats using writhing responses induced by 4% sodium chloride solution. Narcotic and nonnarcotic analgesics, narcotic antagonists except naloxone, and antipyretic and nonsteroidal antiinflammatory drugs were effectively evaluated at relatively low doses using this method. Parenteral ED50 values of these compounds ran parallel to their clinical doses. The method detected not only the analgesic action of the above drugs but also that of methamphetamine. In spite of its high sensitivity, the method was specific in the sense that CNS-depressant, muscle relaxant, anticholinergic, and antihistamine drugs and anesthetics were inactive even at toxic doses. On the other hand, the decrease in the analgesic activity of morphine upon chronic injection was also observed with this method. The writhing test with 4% sodium chloride in rats was concluded to be a sensitive and specific test for analgesic drugs and useful for examining changes in analgesic activity of drugs during chronic administration.

Low tumor incidence in rats with long-term feeding of fusarenon-X, a cytotoxic trichothecene produced by Fusarium nivale

In order to examine tumorigenic effects of fusarenon-X, a trichothecene compound produced by Fusarium nivale, feeding experiments on 151 male Donryu rats were carried out. Daily dose of 105 micrograms (7 ppm in the diet) or 50 micrograms (3.5 ppm)/animal of fusarenon-X was given for 1 or 2 years. Although the animals of the experimental groups showed lower body weight than controls and were more liable to be afflicted by pulmonary infections, tumor incidences were as low as that of the control group. However, several unusual tumors as follows were observed only in the experimental groups: 1 adenocarcinoma of the stomach, 2 papillary carcinomas of the urinary bladder, 1 adrenocortical adenoma, and 1 leukemia.