Synthesis of human endothelin-1 precursors in Escherichia coli

Endothelin, the most potent vasoconstrictor found in nature, is thought to be important in the regulation of blood pressure and/or local blood distribution. Human placenta cDNA fragment encoding preproendothelin-1 (preproET-1) and its carboxyl terminal mature precursor (C-matured precursor) was expressed in E. coli. These products were characterized by both enzyme immunoassay and Western blot analysis.     

Immunohistochemical colocalization of glucagon,serotonin, and aromatic L-amino acid decarboxylase in islet A cells of chicken pancreas

Summary The identity of monoamine-emitted, formaldehyde-induced fluorescence in some pancreatic islet cells was studied in pancreatic tissue of male chickens by fluorescence and immunohistochemistry either on the same tissue section or on serial tissue sections. Pancreatic islet cells emitting intense formaldehyde-induced fluorescence also react immunohistochemically with antisera directed against glucagon, serotonin and aromatic L-amino acid decarboxylase. These results show that chicken pancreatic islet A cells contain glucagon, serotonin, and aromatic L-amino acid decarboxylase, an enzyme involved in the synthesis of serotonin. The islet B cells identified with anti-insulin immunoreactivity, which displayed a very weak formaldehyde-induced fluorescence, did not react with anti-serotonin serum.     

Gender, age and circadian blood pressure variation of apparently healthy rural vs metropolitan Japanese

Interim chronobiologic cardiovascular reference data have been described; 353 clinically healthy Japanese subjects were monitored every 15 min for 24h on 2 occasions. Special attention was paid to the difference between metropolitan and rural areas. Not only the MESORs of SBP and DBP, but also the circadian amplitudes, were higher in the Tokyo than in a rural area (Komaki, Aichi Prefecture). Age-related alterations in the circadian profile of cardiovascular variables were noted for women but not for men. The average MESOR remained similar for SBP in men, whereas in women the average MESOR increased with advancing age in both urban and rural areas. The average circadian amplitude of SBP also increased with age in women, but not in men. No significant deviations of acrophase with age were found for SBP and DBP in men, whereas in rural women the acrophase tended to occur earlier with increasing age.     

Experimental and clinical chronocardiology

Recent advances of the chronobiologic approach to experimental and clinical cardiology was reviewed. First, the maximum entropy method (MEM) was introduced as one of the statistical methods analyzing the circadian periodicity. The MEM power spectrum showed a remarkable resolution property. It will play an important role in chronocardiology in cooperation with the cosinor method. Secondly, recent investigations of the relationship between sleep states and cardiac arrhythmias were mentioned from the viewpoints of both experimental and clinical chronocardiology. Next, recent remarkable advance on myocardial ischemia was reviewed. A marked circadian rhythm in the frequency of myocardial infarction onset and sudden cardiac death has been observed. Lastly, a reference has been made to the recent development of ambulatory BP monitoring. A chronobiologic approach to the analysis of time-series data in cardiology will lead to many advantages in clinical practice.     

Rates of assembly and degradation of bacterial ice nuclei

The kinetics of ice-nucleus assembly from newly synthesized nucleation protein were observed following induction of nucleation gene expression in the heterologous host Escherichia coli. Assembly was significantly slower for the small proportion of ice nuclei active above -4.4 degrees C; this was consistent with the belief that these nuclei comprise the largest aggregates of nucleation protein. The kinetics of nucleus degradation were followed after inhibiting protein synthesis. Nucleation activity and protein showed a concerted decay, indicating that most of the functional ice nuclei are in equilibrium with a single cellular pool of nucleation protein. A minority of the ice nuclei decayed much more slowly than the majority; presumably their nucleation protein was distinct either by virtue of different structure or different subcellular compartmentalization, or because of its presence in a metabolically distinct subpopulation of cells.     

Detection of deoxyribonucleoside-triphosphate imbalance death-induced DNA double strand breakage in FM3A cells by orthogonal-field-alternation gel electrophoresis (OFAGE)

The mechanism of intracellular deoxyribonucleoside-triphosphate (dNTP) imbalance death of mouse mammary tumor FM3A cells was studied. When the cells were exposed to 5-fluorodeoxyuridine, deoxyadenosine, or 2-chlorodeoxyadenosine, dNTP pool imbalance resulted. The imbalance was followed by DNA double strand breaks and subsequent cell death. The DNA double strand breaks have been directly examined by means of orthogonal-field-alternation gel electrophoresis (OFAGE). Fragmented DNA band appeared to be approximately 100-200 kb in size.     

Studies on peptides CLVIII. Model experiments for the synthesis of open-chain unsymmetrical cystine-peptides

Treatment of a mixture of Cys(R)(O) and Cys(R) with an acid was found to generate cystine in fairly good yields, when suitable R, R, and an acid were selected. An unsymmetrical cystine peptide was prepared by treatment of a mixture of Z(OMe)-Cys(R) (0)-Ala-NH₂ (R=Acm or MBzl) and Z(OMe)-Cys(MBzl)-Gly-OBzl with TFA or 1 M TFMSA/TFA.³ Oxytocin was obtained in an excellent yield by TFA treatment of the protected peptide containing Cys(Acm)(0) and Cys(MBzl). Thus, formation of the disulfide bond was found feasible at the position of Cys(R) (0).The following abbreviations are used Boc t-butyloxycarbonyl - Z(OMe) p-methoxybenzyloxycarbonyl - MBzl p-methoxybenzyl - Acm acetamidomethyl - Bzl benzyl - Ad l-adamantyl - tBu t-butyl - TFA trifluoroacetic acid - TFMSA trifluoromethanesulfonic acid - TMSOTf trimethylsilyl trifluoromethane sulfonate     

Effects of subacute treatment with cocaine on activities of N-demethylase, UDP-glucuronyltransferase and sulfotransferase in WKY and SHR rat liver--sex and strain differences

The effects of subacute treatment with cocaine on activities of cocaine N-demethylase, UDP-glucuronyltransferase (GT) toward 4-nitrophenol and phenolphthalein and sulfotransferase (ST) toward androsterone and 4-nitrophenol in livers from Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were investigated. Hepatic metabolism of cocaine was different between the sexes (with males having higher N-demethylase activity) and the strains (with WKY rats having higher activity). The effects of subacute cocaine administration on the activity of cocaine N-demethylase were also sex- and strain-related. Whereas cocaine administration increased activity of hepatic N-demethylase in both female strains, it decreased activity in male WKY and had no effect on activity in male SHR. Sex and strain-related as well as cocaine-induced differences were also found in activities of hepatic GT toward 4-nitrophenol and phenolphthalein as well as in activity of hepatic ST towards andersterone and 4-nitrophenol. These results suggest that some of the individual variation in the effects of cocaine may be due to sex and genetic differences in the hepatic metabolism of cocaine and/or in sexually and/or/genetically-determined differences in how cocaine affects hepatic metabolism of other xenobiotics.     

A simple method for calculation of free metal ion concentrations in the presence of a chelating agent and multiple metal ions by successive approximation

Calculation of free metal ion concentrations in the presence of a chelating agent (ligand) and multiple metal ions is complicated. In this paper we describe a simple method for calculation of free ion concentrations from given total ion concentrations. The outline of this method is as follows: i) Using an arbitrarily chosen provisional value of free ligand concentration (p-Lf), calculate a total ligand concentration (Lt). ii) Divide the p-Lf by the ratio, the calculated Lt (c-Lt)/the specified Lt (s-Lt). Take the resulting value as the next p-Lf and repeat the calculation until c-Lt is close enough to s-Lt. At this point, p-Lf is supposed to be set to a good approximation of true free ligand concentration. iii) Finally, calculate free metal concentrations from the above approximation.