Partial tetrasomy 9(9pter to 9q2101) due to an extra iso-dicentric chromosome.

A 3-year-old boy with partial No. 9 tetrasomy is described. The patient showed markedly retarded physical and mental development as well as multiple congenital anomalies. Routine chromosome analysis revealed an extra C-group chromosome. It had a pronounced secondary constriction at the proximal part of its long arm. Based on studies by a variety of banding techniques, the extra chromosome was identified to be an iso-dicentric No. 9 chromosome with inactivation of one of the two centromeres, the karyotype being 47,XY, + DIC (9)(Q2101). The value of BrdUrd treatment was emphasized in the detection of a very small piece of euchromatin within a long stretch of constitutive heterochromatin.     

Loperamide in rat intestines: A unique disposition

When everted sacs of rat duodenum, jejunum and ileum were incubated with [¹⁴C]loperamide in vitro, unchanged drug and its metabolites were found not only in tissues but also in media of the mucosal side with virtually no radioactivity in media of the serosal side. The amounts of metabolites found in media of the mucosal side were comparable to or larger than those in tissues. Di-desmethyl loperamide was more predominant in the media as compared with mono-demethylated one than in the tissues. Therefore, a portion of loperamide absorbed in intestines can be metabolized there and directly secreted back into lumen. Oral loperamide thus undergoes a unique disposition, likely constituting one of mechanisms for its distinct dissociation of central and antidiarrheal activities.     

Ultraviolet action spectrum for anthocyanin formation in broom sorghum first internodes

An action spectrum for anthocyanin formation in dark-grown broom sorghum (Sorghum bicolor Moench, cv Acme Broomcorn and cv Sekishokuzairai Fukuyama Broomcorn) seedlings was determined over the wavelength range from 260 to 735 nanometers. The action peaks were at 290, 650, 385, and 480 nanometers in descending order of height. The action of the 290-nanometer peak was not affected by subsequently given far red light, whereas those of the other three action peaks were nullified completely. The nullification of the 385-nanometer peak action by far red light was reversible. When an irradiation at these action peaks was followed by a phytochrome-saturating fluence of red light irradiation, the action of the 290-nanometer peak remained, whereas that of the 385-nanometer peak as well as those of the 650- and 480-nanometer peaks was masked by the action of the second irradiation. These findings suggested that the 290- and 385-nanometer action peaks involved different photoreceptors, the latter being phytochrome. The blue light-absorbing photoreceptor as reported to be a prerequisite for phytochrome action in milo sorghum was not found to exist in the broom sorghums.

The action spectrum deprived of the involvement of phytochrome was determined in the ultraviolet region by irradiating with far red light following monochromatic ultraviolet light. The spectrum had a single intense peak at 290 nanometers and no action at all at wavelengths longer than 350 nanometers.

     

Purification and properties of mitochondrial and peroxisomal 3-hydroxyacyl-CoA dehydrogenase from rat liver

There are two 3-hydroxyacyl-CoA dehydrogenase (EC 1.1.1.35) in rat liver, one in mitochondria (type I enzyme), and another in peroxisomes (type II enzyme). In a series of the studies on the properties and the physiological roles of fatty acid oxidation systems in both organelles, the two enzymes were purified and compared for their properties. The final preparations obtained were judged to be homogeneous based on the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sedimentation velocity analysis. Type I enzyme was composed of two identical subunits of molecular weight of 32,000, whereas type II enzyme was a monomeric enzyme having a molecular weight of 70,000–77,000. These subunit structures were confirmed by the results of fluorescence studies. Both enzymes were different in amino acid compositions, especially in the contents of tryptophan and half-cystine. Antibodies against them formed single precipitin lines for the corresponding enzymes, but not for the others when subjected to an Ouchterlony double-diffusion test. The K_m values of type II enzyme for various substrates were lower than those of type I enzyme except those for acetoacetyl-CoA. As for 3-hydroxyacyl-CoA substrates, both enzymes had lower K_m's for longer-chain substrates. The V for the substrates of C₄C₁₀ were similar for each enzyme, though the value of type II enzyme for C₁₀ substrate was rather lower. The results of fluorescence studies suggested that their dissociation constants for NADH were lower and those for NAD⁺ were higher at lower pH. Both enzymes were specific to l-form of 3-hydroxyacyl-CoA substrate. The optimal pH of the forward reaction of type I and type II enzymes was 9.6 and 9.8, and of the reverse reaction, 4.5 and 6.2, respectively. From these results they were concluded to be completely different enzymes.     

Enantiomer selection in the reaction of N-methyl-α-amino acid N-carboxyanhydride and 3-methyl-5-substituted hydantoin: A model reaction for the stereoselective polymerization of α-amino acid N-carboxyanhydride

The addition reaction to N-methyl-(S)-alanine or N-methyl-(S)-phenylalanine N-car-boxyanhydride (NCA) of 3-methyl-5-substituted hydantoin (HDT) catalyzed by a tertiary amine was investigated as a model reaction for the propagation reaction of NCA according to the activated-NCA mechanism. Several activated HDTs having the (S)-configuration of the asymmetric carbon atom were found to react more rapidly than their activated enantiomers. This experimental result indicates that the enantiomer selection by terminal-unit control takes place in the propagation reaction according to the activated-NCA mechanism in which an activated NCA is added to a terminal acylated NCA ring of the growing chain. The enantiomer excess of the HDT recovered from the reaction mixture of N-methyl-(S)-phenylalanine NCA and racemic HDTs activated by a tertiary amine was determined. The extent of the enantiomer selection in the polymerization was found to be 3–10 times as large as that in the model reaction. From these results, it was concluded that the chirality of the penultimate unit, as well as that of the terminal NCA ring, plays an important role in determining the enantiomer selection in the NCA polymerization.     

Gas chromatographic determination of the hypoglycaemic agent gliclazide in plasma

A gas chromatographic method has been developed that permits the accurate and specific determination of the hypoglycaemic agent gliclazide in plasma. Gliclazide is extracted with chloroform and, after clean-up, derivatized with diazomethane followed by heptafluorobutyric anhydride to form N-methyl-N′-heptafluorobutyrylgliclazide, which is assayed on a gas chromatograph equipped with a flame ionization detector, an electron-capture detector or a nitrogen—phosphorus sensitive detector.Accurate determinations are possible with flame ionization detection over a concentration range of 1–15 μg/ml of gliclazide in plasma with a relative standard deviation of 5.2%. The minimum detectable concentration with electron-capture detection is 0.02 μg per sample. Plasma levels of gliclazide in dogs following single oral administration (40 mg per dog) have also been determined.     

Purification and properties of human serum dopamine-β -hydroxylase

1. Two different molecular forms of dopamine-beta-hydroxylase were isolated from human serum; a major component (Peak I enzyme) with a molecular weight of 368000 and with a higher specific activity and a minor component (Peak II enzyme) with a molecular weight of 188000 and with a lower specific activity. 2. Both forms require ascorbic acid for the activity, and are stimulated by fumarate. Addition of N-ethylmaleimide or copper also increased the activity. The optimal pH of both forms in the presence of 20mM tyramine as substrate is 5.0. 3. Km values toward tyramine of Peak I enzyme and Peak II enzyme were 1.67 mM and 14.2 mM respectively. 4. Both Peak I enzyme and Peak II enzyme are glycoprotein.     

Effect of organic acid on gastrointertinal motility of rat invitro

The quantity of organic acids ( lactic acid, acetic acid, propionic acid and butyric acid ) in the content of the gastrointestinal tract of germ-free and conventional rats and the $\text{in}$$\text{vitro}$ effects of the organic acid on the motility of the gastrointestinal tract of rats were investigated.Organic acids were detected only in the gastrointestinal contents of conventional rats but not in those of germ-free rats.Lactic acid detected in the stomach of rats stimulated the motility of both small and large bowel while acetic acid, propionic acid and butyric acid found in the cecum stimulated the motility of the large bowel but not of small bowel.     

Acyl-Coenzyme A synthetase and fatty acid oxidation in rat liver peroxisomes.

Rat liver peroxisomes oxidized palmitate in the presence of ATP, CoA and NAD+, and the rate of palmitate oxidation exceeded that of palmitoyl-CoA oxidation. Acyl-CoA synthetase [acid: CoA ligase (AMP-forming); EC 6.2.1.3] was found in peroxisomes. The substrate specificity of the peroxisomal synthetase towards fatty acids with various carbon chain lengths was similar to that of the microsomal enzyme. The peroxisomal synthetase activity toward palmitate (40--100 nmol/min per mg protein) was higher than the rate of palmitate oxidation by the peroxisomal system (0.7--1.7 nmol/min per mg protein). The data show that peroxisomes activate long chain fatty acids and oxidize their acyl-CoA derivatives.