The active immunoglobulin kappa chain gene is packaged by non-ubiquitin-conjugated nucleosomes

To elucidate the molecular features of active chromatin, we have mapped, by two-dimensional electrophoresis, the protein composition of nucleosomes that package the immunoglobulin kappa chain gene of mouse plasmacytoma cells. Nucleoprotein particles that possess the active kappa chain gene comigrate with bulk mononucleosomes that contain high mobility group proteins HMG-14 or -17 but lack histone H1. High electrophoretic resolution of the underlying core particles, after removal of ubiquitin by isopeptidase treatment, reveals that these nucleosomes are nonubiquitinated, even though they coincidently migrate with bulk ubiquitinated particles. This distinctive electrophoretic behavior may be correlated with the presence of histone H2A.X. Nucleosomes exhibiting these unusual properties appear to span at least 10 kilobases, in both transcribed and nontranscribed regions, suggesting that mechanisms independent of transcription exist to initiate, maintain, and propagate a common chromatin phenotype over long distances along the kappa chain locus.

Improved outcome of renal transplantation with cyclosporine compared with azathioprine--experience in 33 recipients followed for over one year

Long-term clinical aspects after kidney transplantation using cyclosporine (CsA) were studied in 33 patients who received kidney grafts from one haplotype identical living related donor and who were followed for at least one year. Both actual graft and patient survival rates were 97 per cent at one year. Incidence and severity of acute rejection were reduced to a greater extent in patients treated with CsA than in patients treated with azathioprine (AZ). The incidence of infections was low, and no serious bacterial infection occurred in these 33 patients. In 17 of 33 patients with a deteriorative graft function caused by intractable nephrotoxicity, CsA was converted to AZ. The mean serum creatinine level of converted patients was significantly higher than that of patients maintained with CsA at each time when a dose of CsA was stepwise reduced from 14 mg/kg/day to 6 mg/kg/day. Conversion to AZ improved graft function dramatically, although it resulted in reversible acute rejections in 4 patients. CsA induced hepatotoxicity occurred in 10 patients, but in all normal liver function was restored with decrease in the dose. The potent immunosuppressive effect of CsA compensates for its side effects. However, CsA should be converted to AZ when the chronic nephrotoxicity persists at a late stage of post-transplantation.

Characterization of experimental ischemic brain edema utilizing proton nuclear magnetic resonance imaging

Correlations between T1 and T2 relaxation times and water and electrolyte content in the normal and ischemic rat and gerbil brains were studied by means of both nuclear magnetic resonance (NMR) spectroscopic and imaging methods. In the spectroscopic experiment on excised rat brains, T1 was linearly dependent on tissue water content and T2 was prolonged in edematous tissue to a greater extent than expected by an increase in water content, showing that T2 possesses a greater sensitivity for edema identification and localization. Changes in Na+ and K+ content of the tissue mattered little in the prolongation of relaxation times. Serial NMR imaging of gerbil brains insulted with permanent hemispheric ischemia offered early lesion detection in T1- and especially T2-weighted images (detection as soon as 30 min after insult). The progressive nature of lesions was also imaged. Calculated T1 and T2 relaxation times in regions of interest correlated excellently with tissue water content (r = 0.892 and 0.744 for T1 and T2, respectively). As a result, detection of cerebral ischemia utilizing NMR imaging was strongly dependent on a change in tissue water content. The different nature of T1 and T2 relaxation times was also observed.

Substrate recognition of isopeptidase: specific cleavage of the epsilon-(alpha-glycyl)lysine linkage in ubiquitin-protein conjugates

The structural chromatin protein A24 (uH2A) is a conjugate of histone H2A and a non-histone protein, ubiquitin. Eukaryotic cells contain an enzyme, generically termed isopeptidase, which can cleave A24 stoichiometrically into H2A and ubiquitin in vitro. Isopeptidase, free of proteinase activity, has been partially purified from calf thymus by ion-exchange chromatography, gel filtration and affinity chromatography, and analyzed for its substate specificity. There are three major types of isopeptide bonds besides the epsilon-(alpha-glycyl)lysine bond between H2A and ubiquitin; namely, the disulfide bridge, the aldol and aldimide bonds and the epsilon-(gamma-glutamyl)lysine crosslink. Under conditions where A24 was completely cleaved into H2A and ubiquitin, none of these naturally occurring isopeptide bonds was cleaved by isopeptidase. Furthermore, the bonds formed in vitro by transglutaminase reaction between casein and putrescine, through the gamma-NH2 of glutamine residue and the NH2 of putrescine, were not cleaved by the enzyme. The enzyme also failed to cleave the glycyl-lysyl and other orthodox peptide linkages within proteins. Among various proteins examined, the substrates for isopeptidase reaction were confined to conjugates between ubiquitin and other proteins, formed through epsilon-(alpha-glycyl)lysine bonds. Since ubiquitin released by isopeptidase is re-usable for an ATP-dependent conjugation with other proteins, its carboxyl terminal -Gly-Gly-COOH most likely is preserved intact, and is not blocked. These results suggest that isopeptidase specifically recognizes and cleaves the epsilon-(alpha-glycyl)lysine bond. A possible biological significance of this enzyme is discussed.

[Magnetic resonance imaging of experimental cerebral ischemia: correlations between NMR parameters and water content]

Recent studies on proton NMR imaging revealed its remarkable sensitivity for detecting cerebral ischemia. Since proton NMR reflects the distribution and state of water in the brain, an NMR imager becomes a sensitive in vivo detector of brain edema developing soon after the energy state is compromized by ischemia. To further clarify the usefulness of NMR imaging to characterize the ischemia-induced changes, correlations between T1 and T2 relaxation times and water content of the normal and ischemic rat and gerbil brain were studied by means of both spectroscopic and in vivo imaging methods. In the spectroscopic experiment on excised rat brain (cortex, white matter, hippocampus and thalamus for normal and ischemia-laden brain), T1 and T2 relaxation times and water content were determined. The ischemic insult was induced for 60 min by the method of Pulsinelli followed by 60 min of reperfusion. All of the T1, T2 and water content significantly increased in the ischemic tissue. Gray-white difference was evident in T1 and T1 was linearly correlated with the water content of the tissue. T2 was by far prolonged in the ischemic tissue compared with the increase in the water content, showing greater sensitivity of T2 for detection of ischemia. In the imaging experiment, coronal NMR imaging at 0.5 tesla was performed employing proton density-weighted saturation recovery (TR = 1.6 s, TE = 14 ms), T1-weighted inversion recovery (TR = 1.6 s, TI = 300 ms, TE = 14 ms) and T2-weighted spin echo (TR = 1.6 s, TE = 106 ms) pulse sequences.(ABSTRACT TRUNCATED AT 250 WORDS)

[Experimental study on the pathogenesis of acute ulceration in obstructive jaundice--with reference to gastric mucosal blood flow]

We prepared obstructive jaundice models in rats in order to study the mechanism of acute ulceration in obstructive jaundice centering on impediments to gastric wall blood flow and changes in gastric mucosal NA and PGE2 when the rats were subjected to water immersion restraint stress. The results were: In the obstructive jaundice 2 weeks group, when subjected to water immersion restraint stress, gastric mucosal NA reached a dried up stage from the incipient stage, causing gastric mucosal impediments at the same time, showing a significant decrease of gastric mucosal PGE2. Intragastric pH was at a similar level of excessive acidity in all groups; gastric acid is believed to be a secondary factor promoting ulceration. Gastric mucosal PGE2 showed a significant decrease coinciding with the increase in ulceration index, being a possible factor of ulceration; it is also presumed to regulate gastric wall blood flow alternatively with gastric mucosal NA. Pre-treatment with PGE2 prior to loading stress resulted in a decrease in gastric wall blood flow being significantly controlled. The administration of PGE2 brought about an improvement in gastric wall blood flow and a consequent increase in gastric mucosal NA, being judged effective for acute ulceration in obstructive jaundice.

N-band proteins of nucleolar organizers: chromosomal mapping, subnucleolar localization and rDNA binding

The ribosomal DNA(rDNA)-containing chromatin in eukaryotes forms a unique architecture called the "secondary constriction" or "nucleolus organiser region (NOR)" on mitotic chromosomes. To gain more insight into non-histone chromosomal proteins (NHCP), termed "N-band proteins", that are specifically associated with the NOR in a wide variety of eukaryotes, we attempted to: identify the NHCP responsible for N-band staining; determine their stoichiometry; map them on metaphase chromosomes; determine their subnucleolar localization and examine their possible ability to bind rDNA. Based on several criteria, including chromosomal localization, solubility, association with chromatin, and intra-nuclear localization, two of the nucleolus-rich NHCP, termed component B of mol.wt 55,000 and component C of mol.wt. 41,000, were tentatively identified as N-band proteins. Immunological studies using a polyclonal, monospecific antibody raised against component C show that this protein is in fact associated with the chromosomal telomeres where NORs are located. In nucleoli, N-band proteins appear to be compartmentalized into a structure that probably corresponds to fibrillar components. Both components B and C are among several NHCPs that showed, under in vitro conditions, a strong affinity for rDNA cloned in lambda phage but not for calf thymus genomic DNA or phage vector DNA. The antibody against component C effectively suppressed in vitro transcription by RNA polymerase I in nucleoli and nucleolar chromatin. Component C appears to exist in the nucleus at 3.75-5.13 X 10(3) copies per rDNA unit or 0.09-0.13 copy per nucleotide. These findings support the hypothesis that the NOR is a chromosomal site, architecturally not only unique but also different from other chromatin regions in that constituent DNA, i.e., rDNA, is organized in a specific manner by interacting with specific NHCP, i.e., N-band proteins.

Serial changes of plasma cortisol levels during various types of asthmatic responses due to allergen inhalation

To observe possible changes in adrenal function during asthmatic attacks due to allergen inhalation, plasma cortisol levels were measured serially in asthmatic patients who showed immediate asthmatic responses, late asthmatic responses, and dual asthmatic responses were compared with their diurnal levels. There were slightly different patterns of cortisol responses among these groups. In the five patients who showed late asthmatic responses alone, cortisol levels fell significantly during late-type attacks although the decrease was quantitatively small. In the six patients who showed immediate asthmatic responses alone, cortisol levels tended to increase slightly during immediate-type attacks. Cortisol levels in the group with dual asthmatic responses increased slightly during immediate attacks and significantly decreased during late-type attacks, although the decrease was also small.

Idiopathic dilated right ventricular cardiomyopathy: a report of eight cases

From 1970 to 1983, eight patients who had severe right ventricular dilatation with little or no left ventricular abnormality were referred to our hospital. There were two men and six women, whose ages ranged from 16 to 38 years and averaged 27. Five patients were members of two families, which had definite hereditary histories of this disease. ECGs of seven patients suggested right ventricular abnormalities. Ventricular arrhythmias were documented in seven, whose ECGs suggested that the origins of the arrhythmias were in the right or both ventricles. Cardiothoracic ratios ranged from 0.50 to 0.66 and averaged 0.59. Five patients had wide respiratory splitting of the second heart sound. Echocardiography showed a marked increase in the right ventricular dimension. Right ventricular diastolic pressure was increased in three; left ventricular diastolic pressure was increased in two. Right ventricular angiography revealed marked dilatation and low ejection fractions of the right ventricle in all, but left ventricular function was nearly normal in them, except two patients who had minimal abnormality. The average follow-up period was 6.3 years and ranged from 3 months to 11 years. During the follow-up period, only two patients had ventricular tachycardia and three developed overt heart failure. Three patients died, two suddenly, and one from an attack of ventricular tachycardia. Autopsies of these two showed extreme dilatation of the right ventricle and one of them showed concentric hypertrophy of the left ventricle. Histological abnormalities were found in both ventricles. In summary, it is suggested that idiopathic dilated right ventricular cardiomyopathy can be classified in the spectrum of dilated cardiomyopathy.

Quantitative solubilization of nonhistone chromosomal proteins without denaturation using zwitterionic detergents

Of three kinds of commercial zwitterionic detergents [SB 12, SB 14, and 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (Chaps)], SB 12 and Chaps were more useful than SB 14 because of high solubility and less interference with protein assay. Efficiency for protein solubilization at pH 6-9 was higher for SB 12 than for Chaps with either calf thymus chromatin or rat liver nuclei. At pH 9 and ionic strength (I) = 0.35, 1% SB 12 and 1% Chaps were capable of solubilizing about 70% and about 47% of total proteins in rat liver nuclei, respectively. Core histones in rat liver nuclei were extracted to a lesser extent with Chaps than with SB 12. DNA-dependent RNA polymerase and isopeptidase activities were barely inactivated by 1% Chaps at pH 8-9, but isopeptidase activity was inhibited by 0.3% SB 12. These facts indicate that whereas SB 12 is effective for solubilization of whole nuclear proteins, Chaps is suitable for the selective extraction of nonhistone chromosomal proteins without denaturation.

Hepatitis B virus antigen and antibodies in alcoholics. Etiological role of HBV in liver diseases of alcoholic patients

A study was carried out to clarify the pathogenetic role of HBV in alcoholic patients with liver diseases. The incidence of serological markers of HBV infection was investigated in these patients and the histological characteristics were compared among the alcoholic patients with and without HBV markers. A high percentage of patients were positive for either HBsAg, anti-HBs or anti-HBc. In six of eight patients with positive HBsAg, liver histology showed viral features, but in 23 of 39 patients with positive anti-HBs and/or low titre anti-HBc and in 12 of 18 patients with negative HBV markers liver histology showed alcoholic features. From these results it is concluded that HBV presumably plays a major role in the pathogenesis of liver disease in alcoholic patients with persistent HBV infection but not in patients with positive antibodies.