On the degradation of dermorphin and D-Arg2-dermorphin analogs by a soluble rat brain extract

Degradation of dermorphin, [D-Arg2]dermorphin and [D-Arg2, Gly3, Phe4]dermorphin in a soluble rat brain extract was examined. The former two heptapeptides were degraded in a similar fashion to produce corresponding N-terminal tetrapeptide as the main degradation product along with the parallel release of Tyr5, Pro6 and Ser7-NH2. Tyr-D-Arg-Phe-Gly showed a good enzymatic stability. When captopril, an angiotensin-converting enzyme inhibitor, was present in the incubation mixture, hydrolysis of the Gly4-Tyr5 bond was markedly suppressed and resulted in release of the corresponding N-terminal hexapeptide as the main degradation product. Combined use of captopril and amastatin, an aminopeptidase inhibitor, markedly suppressed the hydrolysis of these peptides. On the other hand, [D-Arg2, Gly3, Phe4]dermorphin was hydrolyzed easier than the other two heptapeptides and considerable amounts of Tyr1 and Phe4 were released after 20 hr incubation while the N-terminal tetrapeptide, Tyr-D-Arg-Gly-Phe, showed a good enzymatic stability. On the basis of these results, possible degradation pathways of these heptapeptides were discussed.     

Cell-matrix interrelation and cell-to-cell connection in the secretory ameloblast layer of kitten teeth

To investigate the cell-matrix interrelation and the structure and permeability of the junctional complexes of secretory ameloblasts, molar tooth germs from kittens were examined by means of scanning electron microscopy, routine thin sections and freeze-fracture replication. Scanning electron microscopy showed remarkably dissolved growth fronts of enamel in materials that had been fixed with glutaraldehyde and then subjected to EDTA perfusion for 10 min. By the action of EDTA, intercrystallite spaces in rod and interrod enamel were prominently widened, and their longitudinal ends of crystallites displayed irregular and extremely sparse structures. In enamel rods surrounded entirely by interrod enamel, and in enamel rods of the typical key hole shape with successive interrod enamel participation, the most striking dissolution of crystallites occurred at the boundaries between rod and interrod enamel, where broad expanses of rod-sheath spaces were observed. In thin sections, the Tomes processes of secretory ameloblasts occupying the above rods were rectangular or variations of a rectangular shape, respectively; and interameloblast spaces opened to the enamel growth fronts, which corresponded to the junction between rod and interrod enamel. In enamel rods standing in regular rows and showing the typical arcade shape, the centers of the rods were drastically dissolved and exhibited single and deep slits, whereas the boundaries between rod and interrod enamel showed no wide furrows. The Tomes processes occupying such arcade-shaped rods were typically triangular, and the interameloblast space always joined the type-1 face of process, which is responsible for enamel rod formation. Secretory ameloblast possessed two sets of junctional complexes at the proximal and distal ends of the cell body. The distal one was situated proximally to the Tomes process. Freeze-fracture replication demonstrated the functional structures of these junctions: the proximal junction was fascia occludens, and the distal one incomplete zonula occludens with many free-ending tight junctional strands and interstrand spaces or a less developed irregular junction.     

Amidase-like activity of calpain I and calpain II on substance P and its related peptides

Porcine calpains (Ca2+-dependent cysteine proteinases) I and II, which had been purified each to a homogeneous state, were found to hydrolyze specifically carboxyl-terminal amide of substance P and several other biologically active peptidyl amides. This amidase-like activity was demonstrated both by determining released ammonia and by separating products on high-performance liquid chromatography followed by amino acid analysis. The calpain-catalyzed deamidation of substance P occurred exclusively at the carboxyl-terminal amide, leaving the side-chain glutamine intact. Enkepharinamide and MSH-release inhibiting factor were scarcely deamidated. Calpains I and II showed similar specificities for these amide substances and similar profiles of inhibitions by various protease inhibitors, but distinctly different Ca2+ requirements. The specificity constants, kcat/Km, for substance P were found to be three to four orders of magnitude higher than those for the synthetic substrates.     

Activity of recombinant human alpha interferon against influenza virus infection in mice

The in vivo antiviral activity of recombinant human leukocyte hybrid interferon, HuIFN-alpha AD, was examined. Results showed that this material in highly purified form did not protect mice against a lethal dose of influenza virus, although administration of natural MuIFN-alpha/beta to mice infected with a lethal dose of influenza virus had a marked protective effect. The effect of alveolar macrophages treated with IFN on influenza virus replication was examined in vitro. The antiviral activity of alveolar macrophages treated with HuIFN-alpha AD was lower than that of MuIFN-alpha/beta. It is concluded that HuIFN-alpha AD is effective in direct inhibition of influenza virus, but not in indirect inhibition mediated by alveolar macrophages or in protection of mice from influenza virus infection.     

Long term treatment of congenital hypothyroidism with L-triiodothyronine: 24 year follow-up

A congenital hypothyroidism complicated by ventricular septal defects which was treated with L-triiodothyronine (L-T3) alone from 1 5/12 to 25 years, is described. The patient's growth and development was satisfactory and without side effects. It suggests that L-T3 may be a safe drug for long term treatment of congenital hypothyroidism.     

Sleep-related growth hormone release in thyrotoxic patients before and during propylthiouracil therapy

Hyporesponsiveness of GH to insulin-induced hypoglycemia has previously been reported in hyperthyroid patients. In order to clarify the GH secretion in thyrotoxic patients, sleep-related increases in the serum GH concentration were investigated. Eight thyrotoxic females ranging in age from 7 to 15 were treated with PTU. Blood samples for measurement of GH were drawn every 15 minutes during the first few hours of sleep before and during the treatment lasting about three months. The mean maximum serum GH level before the treatment was 10.0 +/- 5.5 ng/ml (mean +/- SD); this rose to 23.2 +/- 14.6 ng/ml (P less than 0.02) during the treatment. The maximum value of more than 10 ng/ml was detected in only 3 out of the 8 patients before treatment. On the other hand, serum GH levels during PTU administration rose to above 10 ng/ml in all patients except one. It was revealed that sleep-related elevations of GH occurred early in sleep and in close association with a slow-wave EEG pattern. The results show that sleep-related GH release is low in the hyperthyroid state, but becomes significantly elevated during PTU administration. However, even in the hyperthyroid state, the sleep-related secretion of GH is closely correlated with the slow-wave sleep stage as in the euthyroid condition.     

Modulation of postinhibitory increase in plasma prolactin by domperidone in patients with prolactin secreting adenoma

To evaluate the PRL secretory mechanism in patients with PRL-secreting adenoma (PRL-oma), plasma PRL responses to dopamine (DA) were studied in these cases and in normal subjects. Plasma PRL values showed clear decreases during the infusion of DA (5 micrograms/kg/min for 90 min) in both 6 normal and 7 PRL-oma subjects (%decrease: 43.8 +/- 3.9% vs. 53.9 +/- 5.6%; NS) and postinhibitory increases after the termination. However, the postinhibitory increase occurred more promptly and markedly in PRL-oma patients than in normal subjects, i.e. the postinhibitory increase exceeded the basal level 45 min after the termination of DA infusion in PRL-oma patients, whereas the increase in normal subjects did not exceed the basal level even 90 min after the infusion. When domperidone was injected at the termination of DA infusion, the postinhibitory increases were significantly enhanced in either PRL-oma or normal subjects. The maximal increments in plasma PRL in the combination test of DA plus domperidone were significantly larger in PRL-oma patients, but were almost the same in normal controls, compared to the single domperidone test. In contrast, TRH did not modify the postinhibitory rises in 9 PRL-oma patients. These results indicate that the secretory properties and the sensitivities of lactotrophs to decreasing action of DA might be different between PRL-oma patients and normal controls. Further, the postinhibitory rebound phenomenon in PRL-oma patients is possibly determined by an overshoot of PRL storage concomitantly with a decreasing DA action.(ABSTRACT TRUNCATED AT 250 WORDS)     

Efficient synthesis and secretion of a thermophilic alpha-amylase by protein-producing Bacillus brevis 47 carrying the Bacillus stearothermophilus amylase gene.

Bacillus subtilis and Bacillus brevis 47-5, carrying the Bacillus stearothermophilus alpha-amylase gene on pUB110 (pBAM101), synthesized the same alpha-amylase as the donor strain as determined by the enzyme's thermal stability and NH2-terminal amino acid sequence. Regardless of the host, the 34-amino acid signal peptide of the enzyme was processed at exactly the same site between two alanine residues. B. brevis 47-5(pBAM101) secreted the enzyme most efficiently of the hosts examined, 100, 15, and 5 times more than B. stearothermophilus, Escherichia coli HB101(pH1301), and B. subtilis 1A289(pBAM101), respectively. The efficient secretion of the enzyme in B. brevis 47-5(pBAM101) was suggested to be due to the unique properties of the cell wall of this organism.     

Effect of L-propargylglycine on metabolism of sulfur-containing amino acids in pregnant rats and their fetuses

Cystathionine accumulated in several tissues of dams and fetuses by a single intraperitoneal administration of L-proparglyglycine to pregnant rats. Cystathionine in the liver of dams reached its maximal level at about 15 hrs after L-proparglyglycine injection (10 mg/300g), while that in the kidney and brain of dams, and in the liver, kidney, and brain of fetuses reached a maximum at about 21 hrs. The content of cystine in the liver of fetuses decreased gradually in proportion to the amount of L-proparglyglycine administered. Cystathionine gamma-lyase activity in the liver of dams and fetuses decreased to about 2-4% of that of control rats at 15 hrs after L-proparglyglycine injection, and that in the kidney and pancreas of dams to about 10-20% of that of control rats. On the other hand, cystathionine beta-synthase activity did not show significant changes from that of control rats.     

Formation of giant protoplasts from protoplasts of Pleurotus cornucopiae by the cell wall lytic enzyme

Summary When purified protoplasts of Pleurotus cornucopiae IFO9614 were incubated with a mixture of cell wall lytic enzymes, they were found to increase their size. Their average diameter increased from 4.3 m to 31 m after 65 h incubation at 24° C. The presence of cellulase ONOZUKARS in the enzyme mixture had a significant effect on the formation of giant protoplasts. Regeneration frequency of giant protoplasts in a medium containing 0.5 M sucrose was 3.5%, approximately six times that of normal protoplasts.