Quantitative structure–activity relationship (QSAR) study of elastase substrates and inhibitors

One hundred Suc-X-Y-Ala-pNA peptides (SUC: succinyl, pNA: p-nitroanilide, X, Y: Gly, Ala, Val, Leu, Ile, Phe, Pro, x-aminobutyric acid, norvaline, norleucine) were synthesized and their reaction constants with porcine pancreatic elastase (K_m, K_cat and K_cat/K_m) were determined. These reaction constants were quantitatively analyzed using the Free–Wilson/Fujita–Ban method. The contribution of amino acid side chains to the reaction constants K_m, K_cat and K_cat/K_m), expressed logarithmically, was found to be additive. On the other hand, 19 elastase inhibitors of the general formula CF₃CO-X-Y-Ala-pNA (X,Y: ten amino acids) were synthesized, and their inhibition constants were compared with the Michaelis constant for the corresponding substrates and analyzed using free-energy-related substituent constants. In the analysis of amino acid side chains in the Y position, the K_i value of the inhibitor was generally correlated to the K_m value of the substrate, which corresponded to the inhibitor, thus confirming the validity of the equation This study may serve as a prototypical approach to unraveling structure–activity relationships of peptide substrates and inhibitors of medicinal or agricultural importance.     

New Diagnostic Finding to Assess Para-Hisian Pacing Observed in a Patient with a Permanent Form of Junctional Reciprocating Tachycardia

Morphologic Change During Para-Hisian Pacing. Para-Hisian pacing, a useful method to differentiate conduction over an accessory pathway from conduction over the AV node, is assessed essentially by comparing the timing of local atrial electrograms between Hisbundle captured heats and His-bundle noncaptured heats. We describe the case of a patient with a permanent form of junctional reciprocating tachycardia, in whom an atrial double potential was recorded only during the tachycardia at the right posterior septum. During para-Hisian pacing, a morphologic change in the atrial electrogram at the posterior septum was also identified, as well as a change in the retrograde atrial sequence. Since the morphologic change of atrial electrograms during para-Hisian pacing cannot be demonstrated in a patient without an accessory pathway, this new finding could he considered a new additional diagnostic criterion suggesting the presence of an accessory pathway.     

Inhibitory Effects of Daunorubicin on Endothelium-dependent Vasorelaxing Response to Acetylcholine of Rat Aorta

Abstract— The effect of daunorubicin on the endothelium-dependent vasorelaxing response to acetylcholine was investigated using rat isolated aorta and compared with the effect of aclarubicin. Treatment of aortic strips with daunorubicin (20 μM) significantly attenuated the relaxing response to acetylcholine in the absence of tetraethylammonium, but not in its presence. Pretreatment with daunorubicin at a higher concentration (50 μM) or with aclarubicin (20 μM) strongly attenuated the relaxing response to acetylcholine; this attenuation was unaffected by the presence of tetraethylammonium. The increase in aortic cGMP in response to acetylcholine was also significantly suppressed by pretreatment with 50 μM daunorubicin or 20 μM aclarubicin, but not by treatment with 20 μM daunorubicin. The inhibitory effect of 20 μM aclarubicin on the acetylcholine-induced responses was stronger than that of 50 μM daunorubicin. Even in strips pretreated with both 50 μM daunorubicin and 20 μM aclarubicin, relaxation induced by 0·1 μM sodium nitroprusside was retained. These results suggest that daunorubicin at 20 μM inhibits the endothelium-dependent vasorelaxing response to acetylcholine via a mechanism other than the nitric oxide-mediated pathway, whilst at 50 μM, it inhibits the nitric oxide-mediated vasorelaxation.     

Effects of nifedipine on hepatic venous pressure gradient and portal vein blood flow in patients with cirrhosis

Abstract We investigated the effects of nifedipine on splanchnic haemodynamics in 13 patients with cirrhosis and portal hypertension, and in 10 control subjects using hepatic venous catheterization and pulsed Doppler ultrasound. There were no significant changes in systemic or splanchnic haemodynamics in control patients. In contrast, systemic vascodilatation, evidenced by significant decreases in mean arterial pressure and systemic vascular resistance, was observed in patients 20 min after sublingual application of 10 mg nifedipine. Moreover, hepatic venous pressure gradient and portal vein blood flow significantly increased after nifedipine administration. There was a significant correlation between the percentage increases in portal vein blood flow and in hepatic venous pressure gradient. However, no correlation was found between the percentage change in cardiac output and that in portal vein blood flow. Thus the increase in portal vein blood flow appears to be related to splanchnic arterial vasodilatation by nifedipine. Consequently, nifedipine has deleterious effects on portal haemodynamics in patients with cirrhosis. As nifedipine may potentially increase the risk of variceal haemorrhage in patients with less advanced varices, this drug should be used with caution in patients with chronic liver disease.     

Multivariate autoregressive analysis of carotid artery blood flow waveform in an infant of a diabetic mother with cardiomyopathy

We analyzed the carotid artery blood flow waveform (CABFW) of an infant of a non-insulin dependent diabetic mother with hypertrophic cardiomyopathy (IDM cardiomyopathy) through multivariate autoregressive analysis and compared the developmental change of his CABFW with that of normal newborns. The total power was lower than normal newborns on the second and third day of life when his heart dysfunction was severe, and elevated on the fifth day of life when normal-heart function was recovered. The power of component 3 (C3), of which the damping frequency was 7–11 Hz, was slightly high on the second and third day of life and it decreased to the normal range on the fifth day of life by component analysis. In contrast, the power of C3 increased with decreasing resistance index of anterior cerebral artery (RI of ACA) which shows the cerebral vascular resistance of normal newborns. These results suggest that the carotid artery blood flow volume decreased by low cardiac output and the cerebral vascular resistance decreased to maintain the cerebral circulation, when the heart dysfunction was severe.     

Ultrathin films of charged polysaccharides assembled alternately with linear polyions

As a means of preparation of biocompatible molecular surfaces, an alternate assembly of charged polysaccharides and oppositely-charged synthetic polymers was conducted. Cationic chitosan was assembled alternately with anionic poly(sodium styrenesulfonate) (PSS) at pH 4. Regular film growth and its dependence on ionic strength were detected by the quartz crystal microbalance (QCM) method. Averaged film thicknesses for the chitosanCPSS layer were 15, 31, 46, and 69 A° , respectively, when 0, 0.25, 0.5, and 1 M of NaCl was contained in aqueous chitosan. Adsorption of chitosan did not reach saturation in 20 min at 0 M NaCl, while the adsorption became saturated within 6 min with 0.25 M NaCl. Anionic sodium chondroitin sulfate was also assembled in alternation with cationic poly(dimethyldiallylammonium chloride) (PDDA) at pH 6.5. The adsorption of chondroitin sulfate was less sensitive to ionic strength. Surface morphology of chitosan–PSS films was investigated by non-contact atomic force microscopy (AFM) observation. Maximum height difference and Ra value for a 1000 × 1000 nm area were 11 and 0.69 nm, respectively, indicating the formation of a molecularly flat surface by alternate layer-by-layer adsorption.     

Problems on the diagnosis of sudden infant death syndrome

Various autopsy cases of sudden unexpected death (SUD) in infancy were examined at the Tokyo Medical Examiner's Office between 1985 and 1994. More than half of the SUD were diagnosed as sudden infant death syndrome (SIDS), but a number of other causes, such as mechanical asphyxia, were also diagnosed. SIDS is diagnosed by autopsy, but there are no clear diagnostic criteria differentiating SIDS from other causes of SUD. SUD is diagnosed as SIDS when other causes are excluded, but it is difficult to distinguish between SIDS and mechanical asphyxia. There was not a large difference in autopsy findings, or in death scene or statistical data, between SIDS and non-SIDS cases. In their estimation of the diagnostic ratio of SIDS to other causes of death, medical examiners might be divided into three groups: ‘SIDS tolerationist’ examiners think that SUD should be positively diagnosed as SIDS, insofar as another cause of death is not proved clearly. A second group of examiners might be regarded as ‘SIDS exclusionist’; these consider microscopic findings or peculiar death scenes as important contributing factors leading to death. The third group represents a middle stance somewhere between these two. We thought that (forensic) pathologists as well as medical examiners in Japan might have differing stances on SIDS diagnosis. The statistical analysis of SIDS in certain research areas may be affected by the diagnostic ‘preference’ of pathologists belonging to a certain institute.     

Developmental change in carotid artery blood flow waveform by component analysis in children

The carotid artery blood flow waveform (CABFW) is regarded as a summation of cardiac impulse responses. These impulse responses are divided into several components through a two-dimensional autoregressive modelling approach. Using this approach, we determined the developmental change in CABFW in 94 normal subjects from the neonatal period to adolescence. Our analysis demonstrated that: (i) the total power of impulse response increased significantly with increasing age. The component of impulse response was divided into six groups according to the damping frequency: group I (0 Hz), group II (1–5 Hz), group III (5–8 Hz), group IV (8–13 Hz), group V (13–17 Hz) and group VI (> 17 Hz); (ii) the power-density and the damping time of group I and II impulse response increased significantly with increasing age; (iii) the power-density and percent power of group III impulse response and power-density of group IV impulse response increased significantly with increasing age. Our results indicated that CABFW contained some regular impulses and that group I, II, III and IV, which were influenced by several factors, including cardiac contraction and the compliance and frictional forces of the carotid artery, appeared to be important to the developmental change of CABFW in children.     

Results for 79 patients with neuroblastoma detected through mass screening at 6 months of age in a single institute

BACKGROUND: In Japan, mass screening for neuroblastoma has been performed at 6 months of age to improve the prognosis of this condition for more than 20 years. In recent years, most neuroblastomas detected by mass screening were considered to have favorable biological features and sometimes tend to regress spontaneously. METHODS: The authors established non-treated observation criteria in 1997 and criteria for observation of residual tumor after first-line chemotherapy in 1999, and have made an effort to reduce the intensity of medical treatment for neuroblastoma. The authors examined outcomes of 79 patients who were found in the Shizuoka neuroblastoma mass screening at 6 months of age and who received medical treatment or underwent observation in Shizuoka Children's Hospital, Shizuoka, Japan, between December 1981 and December 2004. RESULTS: A total of 77 patients survived but the remaining two patients died from complications of medical treatment. None of the patients died due to progression of neuroblastoma. In the cases, non-treated observation was performed in 17. Of those, 12 patients are now under non-treated observation. Of their tumors, two have disappeared, nine have become smaller and another one has not change in size. Observation of residual tumor after first-line chemotherapy was performed in 15 cases, and three disappeared and the other 12 cases became smaller. Medical treatment-related complications were observed in 20 of 67 patients who received medical treatment, and 18 of the 20 patients were seen before establishing non-treated observation criteria. CONCLUSION: Non-treated observation and observation of residual tumor after first-line chemotherapy were useful to reduce medical treatment-related complications.     

Subchronic Oral Toxicity of Glyoxal via Drinking Water in Rats

Subchronic Oral Toxicity of Glyoxal via Drinking Water in Rats.Ueno, H., Segawa, T., Hasegawa, T., Nakamuro, K., Maeda, H.,Hiramatsu, Y., Okada, S., and Sayato, Y. (1991). Fundam. Appl.Toxicol. 16, 763–772. The subchronic oral toxicity ofglyoxal via drinking water and the effect on in vivo proteinsynthesis in tissues following a single treatment with thissubstance were assessed in Sprague–Dawley male rats. Animalsreceived drinking water containing glyoxal levels of 2000, 4000,and 6000 mg/liter ad libitum for 30, 60, and 90 days in PhaseI. In Phase II, the high-dose and control-1 groups fed the dietad libitum, and a diet-limited control-2 group given the sameamount of diet as consumed by the high-dose group were maintainedfor 90 and 180 days. The study designs included observationsof clinical signs, body weights, major organ weights, grossand histopathological examinations, serum clinical chemistry,and biochemical examinations such as glyoxalase activity andglutathione content in selected tissues. Body weight gain andorgan weights significantly decreased with dosage. Althoughconsumption of food and water was also depressed in the exposedgroup, the reduction of body weight gain was greater in thehigh-dose group than in the diet-limited control 2 group. Histopathologicalexaminations revealed only a slight papillary change in thekidneys from the high-dose group at both 90 and 180 days terminationsin Phase II. The induction of both glyoxalase I and II was observedin liver and erythrocytes at 30-day termination of the exposedgroups. Serum enzyme and protein levels were significantly reducedby the mid- and/or high-dose exposures. With a single oral high-dosetreatment of glyoxal, a great decline in the incorporation ofL-[³H]leucine was shown particularly in the liver, and thisprobably led in part to a reduction in the serum protein levelsin rats following subchronic exposure to glyoxal. These dataindicated an overall low degree of systemic toxicity to ratsexposed subchronically to glyoxal via drinking water.