Fatty acid beta-oxidation system in microbodies of n-alkane-grown Candida tropicalis.

Localization of fatty acid beta-oxidation system in microbodies of Candida tropicalis cells growing on n-alkanes was studied. Microbodies isolated from the yeast cells showed palmitate-dependent activities of NAD reduction, acetyl-CoA formation and oxygen consumption. When sodium azide, an inhibitor of catalase, was added to the system, palmitate-dependent formation of hydrogen peroxide was observed. Stoichiometric study revealed that two moles of NAD were reduced per one mole of oxygen consumed in the absence of sodium azide and the presence of the inhibitor doubled the oxygen consumption by microbodies without an appreciable change in NAD reduction. These results indicate that the yeast microbodies contain beta-oxidation system of fatty acid, and that catalase located in the organelles participates in the degradation of hydrogen peroxide to be formed at the step of dehydrogenation of acyl-CoA.     

Physiologic evidence for descending tryptaminergic pathways in the spinal cord.

LSD was more effective in facilitating the flexor reflex in the chronic than in the acute spinal dog. On the other hand, $\text{1}$-tryptophan produced a significant facilitation of the flexor reflex in the acute spinal dog but not in the chronic spinal dog. These data are consistent with the hypothesis that there are long descending tryptaminergic axons which have the capacity of converting tryptophan to tryptamine and releasing it in the vicinity of post-synaptic facilitatory receptors which degenerate in the chronic spinal dog.     

Monoamine fluorescence in the median eminence of the Japanese quail,Coturnix coturnix japonica,following medial basal hypothalamic deafferentation

Summary Monoamine fluorescence was examined in the ventral hypothalamus of the Japanese quail, Coturnix coturnix japonica after medial basal hypothalamic deafferentation. In sham-operated control birds, numerous yellow-green fluorescent fibers were observed in the median eminence and the nucleus tuberis. In the area of the paraventricular organ, a number of fluorescent fibers and cell bodies were observed. In birds with deafferented hypothalami, fluorescence disappeared both in the median eminence and the nucleus tuberis. In the area of the paraventricular organ, which was within the area of deafferentation, fluorescence of neuronal perikarya did not change, but fluorescent fibers decreased markedly in number. Disappearance of monoamine fluorescence in the median eminence and the nucleus tuberis is discussed in relation to the tanycyte absorptive function and gonadal development.Supported by Grants from the Ministry of Education to Professors T. Bando and H. Kobayashi, and a Grant from the Ford Foundation to Prof. H. Kobayashi.     

Tanycyte absorption affected by the hypothalamic deafferentation in Japanese quail,Coturnix coturnix japonica

In Japanese quail, Coturnix coturnix japonica the tanycytes of the median eminence absorbed peroxidase injected into the third ventricle. The number of tanycytes showing peroxidase reaction was greater in the posterior median eminence than in the anterior median eminence. Following hypothalamic deafferentation, the tanycyte absorption was augmented both in the posterior and anterior median eminence. These findings suggest that axons of some neurons, which have inhibitory action on the tanycyte absorption, were transected by deafferentation resulting in augmentation of tanycyte absorption. A considerable number of ependymal cells lining the upper portion of the third ventricle and those of the pars nervosa also absorbed peroxidase. In birds with a deafferented hypothalamus, photostimulated ovarian growth was completely inhibited.     

Determination of tryptophan, tyrosine, and phenylalanine by second derivative spectrophotometry

Second derivative spectrophotometry has been useful for the determination of aromatic amino acids. However, published methods produce erroneous results, because those methods measure second derivative values by the vertical distance between peak and trough which is subject to variation according to the aromatic amino acid composition of proteins. This paper presents a method of second derivative spectrophotometry which measures second derivative absorbance values by means of the vertical distance from baseline to the derivative curve at a wavelength specifically assigned to each aromatic amino acid, and makes corrections for the interference from other amino acids at the same wavelength. The Appendix describes a computational method for obtaining absolute values of second derivative absorbances directly from normal absorbance values without using the spectrophotometer's derivative mode, because most commercial instruments produce completely arbitrary second derivative values which make comparison of data obtained on two different instruments impossible.     

Centriole and PCM cooperatively recruit CEP192 to spindle poles to promote bipolar spindle assembly

The pericentriolar material (PCM) that accumulates around the centriole expands during mitosis and nucleates microtubules. Here, we show the cooperative roles of the centriole and PCM scaffold proteins, pericentrin and CDK5RAP2, in the recruitment of CEP192 to spindle poles during mitosis. Systematic depletion of PCM proteins revealed that CEP192, but not pericentrin and/or CDK5RAP2, was crucial for bipolar spindle assembly in HeLa, RPE1, and A549 cells with centrioles. Upon double depletion of pericentrin and CDK5RAP2, CEP192 that remained at centriole walls was sufficient for bipolar spindle formation. In contrast, through centriole removal, we found that pericentrin and CDK5RAP2 recruited CEP192 at the acentriolar spindle pole and facilitated bipolar spindle formation in mitotic cells with one centrosome. Furthermore, the perturbation of PLK1, a critical kinase for PCM assembly, efficiently suppressed bipolar spindle formation in mitotic cells with one centrosome. Overall, these data suggest that the centriole and PCM scaffold proteins cooperatively recruit CEP192 to spindle poles and facilitate bipolar spindle formation.     

Basal and Ischemia-Induced Transcardiac Troponin Release into the Coronary Circulation in Patients with Suspected Coronary Artery Disease

Background

Cardiac troponin is a specific biomarker for cardiomyocyte necrosis in acute coronary syndromes. Troponin release from the coronary circulation remains to be determined because of the lower sensitivity of the conventional assay. We sought to determine basal and angina-induced troponin release using a highly sensitive troponin assay.

Methods and Results

The cardiac troponin T levels in serum sampled from the peripheral vein (PV), the aortic root (AO), and the coronary sinus (CS) were measured in 105 consecutive stable patients with coronary risk factor(s) and suspected coronary artery disease (CAD) and in 33 patients without CAD who underwent an acetylcholine provocation test. At baseline, there was a significant increase in the troponin levels from AO [9.0 (6.4, 13.1) pg/mL for median (25^th, 75^th percentiles)] to CS [10.3 (7.3, 15.5) pg/mL, p<0.001] in 96 (91.4%) patients and the difference was 1.1 (0.4, 2.1) pg/mL, which reflected basal transcardiac troponin release (TTR). TTR was positively correlated with PV levels (r = 0.22, p = 0.03). Male sex, left ventricular hypertrophy determined by echocardiography, T-wave inversion, and CAD correlated with elevated TTR defined as above: median, 1.1 pg/mL. A significant increase in TTR was noted in 17 patients with coronary spasms [0.6 (0.2, 1.2) pg/mL, p<0.01] but not in 16 patients without spasms [0.0 (−0.5, 0.9) pg/mL, p = 0.73] after the acetylcholine provocation.

Conclusion

Basal TTR in the coronary circulation was observed in most of the patients with suspected CAD and risk factor(s). This sensitive assay detected myocardial ischemia-induced increases in TTR caused by coronary spasms.