myc-related proteins and DNA sequences in Trypanosoma brucei

The cAMP content of Trypanosoma brucei increases in parallel with ascending mammalian parasitemia to very high levels just before differentiation of the long-slender to the short-stumpy bloodstream form. Because expression of myc oncogenes is required for vertebrate cells to interpret proliferation signals and declines in response to cAMP mediated differentiation, we investigated whether T. brucei also harbored myc-like proteins and genes. Accordingly, we probed lysates of long-slenders, short-stumpies and procyclics (insect midgut stage) with antibody to myc proteins and also hybridized myc gene family sequences to procyclic DNA. We found that antibody to myc-family proteins of mammals reacts with 40 kDa and 55 kDa proteins in all three life cycle stages, and that procyclic DNA contains three EcoRI fragments that are homologous to a v-myc probe. One of these fragments also hybridizes to a synthetic 25-mer oligonucleotide deduced from a consensus sequence in the second exon of the myc family and expresses a 3.2 kb mRNA transcript in Northern blots of procyclic RNA. The conservation of myc-family homologous across the broad phylogenetic gap between mammals and trypanosomes illustrates ancient evolutionary relationships and raises the possibility of stage-specific expression of myc genes during the life cycle of T. brucei.

Probes for narcotic receptor mediated phenomena. 15. (3S,4S)-(+)-trans-3-methylfentanyl isothiocyanate, a potent site-directed acylating agent for the delta opioid receptors in vitro

Recently we reported the synthesis of the first enantiomeric pair of irreversible opioid ligands [(3S,4R)-(-)- and (3R,4S)-(+)-cis-4, SUPERFIT] and specific interaction of the latter with the delta receptor. Here we report another enantiomeric pair of irreversible opioid ligands, (+)-trans- and (-)-trans-3-methylfentanyl isothiocyanates [(3S,4S)-(+)-trans- and (3R,4R)-(-)-trans-4]. A single-crystal X-ray analysis of the 2,4,6-trinitrobenzenesulfonic acid salt of (+)-trans-3-methyl-N-phenyl-4-piperidinamine [(+)-trans-8] revealed it (and, therefore, 4) to have the trans configuration and the absolute configuration of (+)-trans-8 to be 3S,4S. The (+)-trans enantiomer of 4 was shown to be highly potent and about 10-fold more selective as an acylating agent than (-)-trans-4 for the higher affinity [3H]DADL (delta) binding site in rat brain membranes. In that assay, (+)-trans-4 and (+)-cis-4 were essentially equipotent as affinity ligands, and the levo enantiomers were considerably less potent. (+)-trans-4 was, thus, a potent, subtype-selective acylating agent for the delta opioid receptor in vitro. With membranes from NG108-15 neuroblastoma x glioma hybrid cells, containing only delta receptors, (+)-cis-4 was found to be a little more potent than (+)-trans-4. Similarly, (+)-cis-4 is the most effective inhibitor of adenylate cyclase in these membranes, (+)-trans-4 has weak activity, and the levo enantiomers are inactive. Only (+)-cis-4 was found to have antinociceptive activity in vivo.

Effect of the hinge protein on the heme iron site of cytochrome c1

X-ray absorption spectroscopic (XAS) studies on cytochrome C1 from beef heart mitochondria were conducted to identify the effect of the hinge protein [Kim, C.H., & King, T.E. (1983) J. Biol. Chem. 258, 13543-13551] on the structure of the heme site in cytochrome c1. A comparison of XAS data of highly purified "one-band" and "two-band" cytochrome c1 [Kim, C.H., & King, T.E. (1987) Biochemistry 26, 1955-1961] demonstrates that the hinge protein exerts a rather pronounced effect on the heme environment of the cytochrome c1: a conformational change occurs within a radius of approximately 5 A from the heme iron in cytochrome c1 when the hinge protein is bound to cytochrome c1. This result may be correlated with the previous observations that the structure and reactivity of cytochrome c1 are affected by the hinge protein [Kim, C.H., & King, T.E. (1987) Biochemistry 26, 1955-1961; Kim, C.H., Balny, C., & King, T.E. (1987) J. Biol. Chem. 262, 8103-8108].

Floxuridine-induced sclerosing cholangitis: an ischemic cholangiopathy?

A 43-year-old man underwent abdominoperineal resection of a rectal adenocarcinoma, and left hepatic lobectomy for a single metastasis. He then received hepatic artery infusions of floxuridine. The tumor did not recur, but sclerosing cholangitis and liver failure developed which necessitated orthotopic liver transplantation. In the hilus of the native liver, obstructive arteriopathy and portal venopathy were found. These lesions probably had been caused by drug-induced intravascular thrombosis. Thus, the sclerosing cholangitis that develops in many patients after floxuridine infusion may be ischemic rather than toxic. The patient described here is well, 14 months after orthotopic liver transplantation. Therefore, in some cases of floxuridine-induced cholangitis, liver transplantation appears to be indicated despite a history of metastasizing carcinoma.

Effect of inhibition of prostaglandin synthesis on epinephrine-induced gastroduodenal electromechanical changes in humans

We conducted a double-blind randomized study to investigate the role of endogenous prostaglandins in epinephrine-induced changes in human gastric electromechanical activity. Intravenous administration of a pharmacologic dosage of epinephrine (222 ng/kg per min) caused gastric dysrhythmia in 8 of 12 healthy subjects. After indomethacin treatment, the incidence of epinephrine-induced gastric dysrhythmia was reduced to 4 of 12 healthy subjects, which is similar to the incidence of gastric dysrhythmia noted in the placebo group. The difference, however, was not statistically significant (P = 0.2). Epinephrine also substantially inhibited both the amplitude and the frequency of antral contractions. Indomethacin treatment partially reversed the reduction in the amplitude but not the frequency of antral contractions. These results suggest that endogenous prostaglandins may, in part, regulate the amplitude of human antral contractions; however, the role of prostaglandins in epinephrine-induced gastric dysrhythmia in humans remains uncertain.

Korean version of the Geriatric Social Readjustment Questionnaire: cross-cultural comparison between Koreans and Americans in the perception of life events

The purpose of this study was to construct a Korean version of the Geriatric Social Readjustment Questionnaire (K-GSRQ), to investigate its applicability to the elderly and to compare cross-cultural differences in the perception of the life events between Koreans and Americans. The K-GSRQ consists of 33 items. Most of the life events considered as crucial in old age were similar in ranking in comparison between Koreans and Americans. Some differences in ranking can be attributed to the differences in Socio-cultural backgrounds. The K-GSRQ was applied to controls, neurotic cases and cases with physical illnesses. The result suggest that the Korean version of the Geriatric Social Readjustment Questionnaire is applicable for the study of the health status of the elderly in Korea.

Idiopathic cyclic nausea and vomiting--a disorder of gastrointestinal motility?

Eight patients (five men and three women) with previously unexplained recurrent cyclic episodes of nausea and vomiting are described. In these patients, the symptoms developed a mean of once every 3.2 months and persisted a mean of 3.5 days. None of the patients had an identifiable cause of their symptoms on conventional diagnostic tests. A detailed investigation of the gastrointestinal motility during an asymptomatic period revealed abnormal findings in all eight patients. Gastric hypomotility was substantiated in five patients, small bowel dysmotility in six, delayed gastric emptying in two, and gastric dysrhythmia in two. The data demonstrate that abnormal gastrointestinal motility occurs during an asymptomatic state in patients with cyclic episodes of nausea and vomiting. Because all patients with this syndrome had abnormal gastrointestinal motility but normal results of other gastrointestinal studies, idiopathic cyclic nausea and vomiting may be related to altered gastrointestinal motility.

Deterioration of membrane morphology, phospholipids, and cytoskeletal protein in rat erythrocytes exposed to tert-butyl hydroperoxide: protection by exogenous glutathione fails in selenium deficiency

Here we report scanning electron microscopy, phospholipid and fatty acid composition and cytoskeleton proteins of erythrocytes from Se-adequate and Se-deficient rats, showing protection by glutathione (GSH) against tert-butyl hydroperoxide (t-BuOOH)-induced hemolysis of erythrocytes from Se-adequate, but not from Se-deficient rats. Without exogenous GSH, erythrocytes incubated with t-BuOOH exhibited remarkable deterioration of cell membranes with diminished membrane phosphatidyl-ethanolamine, -serine, and -inositol and selective loss of a cytoskeletal protein, ankyrin 2-1. Without exogenous GSH these changes occurred in erythrocytes from both Se-deficient and Se-adequate rats. Dietary Se, through provision of glutathione peroxidase (GSH-Px) in erythrocytes as a probable scavenger of t-BuOOH, protects against hemolysis when GSH is available.

Evidence for a delta-class opioid receptor on cells of the immune system

Opioid receptors have been reported to be present on cells of the immune system. Both opioid receptor-ligand interactions which are reversible by naloxone (classical) and those interactions which are irreversible by naloxone (nonclassical) appear to alter various immunologic parameters through the ligand-receptor interactions. In an effort to characterize opioid receptors (which operate with classical interactions) on cells of the immune system, we employed the delta-class opioid receptor-specific ligand, cis-(+)-3-methylfentanylisothiocyanate (SUPERFIT). We herein report the specific labeling of a protein with a molecular weight of 70,000 Da under reducing conditions (58,000 Da under nonreducing conditions) from both B and T cell-enriched murine splenocytes and peripheral blood lymphocytes. Similar results are demonstrated by human peripheral blood lymphocytes and plastic-adherent (monocyte-enriched) leukocytes.

tert-butyl hydroperoxide-induced hemolysis of alpha-tocopherol-decreased erythrocytes from selenium-deficient and selenium-adequate rats

The protective function of alpha-tocopherol, glutathione (GSH), and glutathione peroxidase (GSH-Px) from tert-butyl hydroperoxide (t-BuOOH)-induced hemolysis was studied with the erythrocytes from male Wistar rats fed selenium (Se)-adequate or -deficient diet for 3 months. By the preincubation with a water-soluble radical initiator, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH), at 10 mM for 6 h at 37 degrees C, alpha-tocopherol levels of the erythrocytes were decreased to 40% of the original level, that is, to the level insufficient for supporting the normal functions of the erythrocytes. With the Se-deficient cells, the hemolysis proceeded rapidly irrespective of the presence or absence of GSH in the incubation medium, and irrespective of the presence or absence of AAPH in the preincubation medium. Contrarily, GSH suppressed the hemolysis of Se-adequate cells which were preincubated with and without AAPH. These results are consistent with the notion that Se serves as the prime, important defense mechanism in the t-BuOOH-induced hemolysis through the activity of GSH-Px. Either alpha-tocopherol or GSH by itself, or both by themselves, may not play so significant a role as Se does in suppressing the hemolysis.

Cardiac amyloidosis diagnosed by endomyocardial biopsy

A 56-year-old male patient who had a history of syncopal attack was diagnosed as having cardiac amyloidosis. His ECG finding showed a pattern of inferior and anteroseptal wall infarction with Wenckebach AV block.

Echocardiographic examination revealed that the LV posterior wall and interventricular septum were markedly thickened with granular sparkling.

We demonstrated the amyloid deposit in the myocardium by endomyocardial biopsy.

Pathology showed a green white birefringence by polarizing illumination and amyloid fibril in electron microscopic study.

Effect of gastric dysrhythmias on postcibal motor activity of the stomach

The effect of electrical dysrhythmias on the mechanical activity of the fed stomach was investigated in 5 conscious dogs implanted with Ag-AgCl electrodes and strain gauge force transducers. Each dog was fed 1 can of ALPO and electromechanical activities of the stomach were recorded for the next 120 min. The results show that intraarterial boluses of met-enkephalin (75 micrograms/kg), PGE2 (36 micrograms/kg), and epinephrine (36 micrograms/kg) induced episodes of antral dysrhythmias whereas saline (1 cc) did not. The postcibal antral motility index for the test period was not altered following saline injection, but it was reduced by 61%, 70%, and 81% following the administration of met-enkephalin, epinephrine, and PGE2, respectively (p less than 0.01 vs. baseline period). During periods of normal electrical rhythm, PGE2 and epinephrine significantly reduced the antral motility index (2.07 +/- 0.93 and 3.24 +/- 0.79, respectively) vs. saline (7.92 +/- 0.44) (p less than 0.05 for both drugs) whereas met-enkephalin (4.98 +/- 0.56) did not. In contrast, during episodes of dysrhythmia, met-enkephalin significantly depressed antral motility (1.70 +/- 0.74) (p less than 0.05 vs. periods with normal electrical rhythm) whereas neither epinephrine nor PGE2 caused a further reduction in antral motility from what was seen during periods of normal electrical rhythm (1.84 +/- 0.72 and 1.34 +/- 0.37, respectively). We thus conclude that intraarterial administration of met-enkephalin, PGE2, or epinephrine induce gastric dysrhythmias postcibally and depress antral contractile activity. The relaxatory effect of met-enkephalin on antral contractions is primarily due to its dysrhythmic effect whereas PGE2 and epinephrine inhibit antral motility even when the electrical rhythm is undisturbed.

Induction of Symbiotically Defective Auxotrophic Mutants of Rhizobium fredii HH303 by Transposon Mutagenesis

Symbiotically defective auxotrophic mutants were isolated by transposon Tn 5 mutagenesis of Rhizobium fredii HH303, a fast-growing microsymbiont of North American commercial soybean cultivars such as Glycine max cv. Williams. Three different Tn 5 -carrying suicide vectors, pBLK1-2, pSUP1011, and pGS9, were used for mutagenesis with transposition frequencies of 4 × 10 −5 , 3 × 10 −6 , and 1 × 10 −6 , respectively, while the frequency of background mutation resistant to 500 μg of kanamycin per ml was 1 × 10 −8 . From 2,600 Tn 5 -induced mutants, 14 auxotrophic mutants were isolated and classified in seven groups including adenosine (four), aspartate (two), cysteine or methionine (two), isoleucine and valine (two), nicotinic acid (one), pantothenic acid (one), and uracil (two). All the auxotrophs induced nodulation on soybean, but the symbiotic effectiveness of each mutant was different. Three auxotrophs (two cysteine or methionine and one pantothenic acid) formed effective nodules similar to those of the wild type. Three auxotrophs (one nicotinic acid and two aspartate) produced mature nodules like those of the wild type, but the nodules lacked the characteristic pink color inside and were unable to fix nitrogen. Four auxotrophs (two adenosine and two uracil) induced pseudonodules unable to fix nitrogen. The other four auxotrophs repeatedly induced both effective and ineffective nodules, but bacteroids isolated from the effective nodules were prototrophic revertants. The symbiotic phenotype and the degree of effectiveness of the auxotrophic mutants varied with the type of mutation.

Noninvasive evaluation of left ventricular diastolic function in patients with angina pectoris--pulsed Doppler echocardiographic technique

To assess the disturbed left ventricular diastolic filling by pulsed Doppler echocardiography in patients with angina pectoris who have normal systolic function, 55 subjects (33 angina patients with, 22 control subjects without significant (⩾75%) coronary artery narrowing) underwent pulsed Doppler echocardiography examination one day before coronary arteriography. From analysis of the transmitral flow velocity curve, diastolic time intervals, peak early and late atrial flow velocities, the ratio of early to atrial peak flow velocity, and deceleration slope after peak early flow velocity were measured. The angina group had a significantly higher peak atrial flow velocity (50.1 ± 10.0 cm/sec vs. 43.7 ± 9.0, p<0.05) and a lower ratio of early to atrial peak flow velocity (0.91 ± 0.24 vs. 1.17 ± 0.30, p<0.005), but peak early flow velocity, deceleration slope, and diastolic time intervals were similar in both groups. Therefore, the pulsed Doppler technique using the transmitral flow velocity curve is thought to be useful in the noninvasive evaluation of diastolic function even in patients with angina pectoris who have normal systolic function and no left ventricular hypertrophy.

Studies on mikamycin B lactonase. V. Metabolic control in mikamycin B fermentation

In mikamycin B fermentation, some procedures were examined to remove the participation of mikamycin B lactonase, which reduces mikamycin B titers. Addition of enzyme inhibitors and control of pH resulted in the elimination of the enzyme activity, and in the stimulation of antibiotic production.

Isolation and identification of beta-nitrostyrene from smoked chicken

Extraction and identification of beta-nitrostyrene from smoked chicken is described. Commercially obtained smoked chicken was homogenised and extracted with chloroform-methanol (2:1). The extracts were fractioned by silicic acid column chromatography. The purified extract using thin-layer chromatography was identified by a colour reaction (this qualitative method for some nitrated compounds is developed this time), high pressure liquid chromatography and gas chromatography/mass spectrometry. The concentration of beta-nitrostyrene in the smoked chicken was 94 ppb. The average recovery of added beta-nitrostyrene was 107%. However, the toxicity of this material was not tested in the present paper.

Radiofrequency hyperthermia for malignant brain tumors: preliminary results of clinical trials

Local hyperthermia by 13.56-MHz radiofrequency (RF) capacitive heating was evaluated in 16 patients with malignant brain tumors. Intracranial heating during operation was performed in 4 patients. RF applicators with a cooling system were placed on the cerebral convexity and medial brain surface with the tumor between them. RF power was controlled to maintain the brain temperatures under 40 degrees C. Under this condition, the highest temperature of each tumor varied from 44 to 49 degrees C. After heating for about 60 minutes, 2 tumors showed regression on computed tomographic (CT) scans. Extracranial heating was performed in 12 patients with cerebral glioblastoma. RF applicators were placed on the lateral sides of the scalp and applied to diametrically opposite sides of the tumor. To avoid the influence of the skull on RF conduction, we performed a bilateral craniectomy slightly larger than the applicator at the initial operation. Heating was performed for approximately 60 minutes at each session and was repeated twice a week for a total of 4 to 10 times in combination with radiation and ACNU chemotherapy. No anesthetic agent was used during heating. Brain temperatures were maintained under 42 degrees C. The scalp under the applicators remained at 28-35 degrees C during heating, and no heat injury of the scalp was observed after repeated heating. The highest temperatures of the tumor or cavity after tumor removal were 45-46 degrees C in 3 cases, 43-44 degrees C in 3 cases, 42-43 degrees C in 4 cases, and 40-41 degrees C in 2 cases, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Meal reduces sensitivity of the stomach to pharmacologically induced dysrhythmia

The aim of this study was to determine whether food ingestion causes a change in the susceptibility of the stomach to dysrhythmia or in the characteristics of gastric dysrhythmia. The susceptibility of the stomach to develop dysrhythmia was measured by determining the median effective dose of four different drugs known to produce gastric dysrhythmia. These drugs were epinephrine, PGE2, met-enkephalin, and glucagon. The median effective dose for inducing gastric dysrhythmia was measured in four healthy conscious dogs by Dixon's up-and-down method during fasting and after feeding. The median effective dose of epinephrine, PGE2, met-enkephalin, and glucagon were higher after feeding (16.6, 16.6, 35.1, greater than 221 micrograms/kg, respectively) than during fasting (1.7, 5.2, 11.1, 61.0 micrograms/kg, respectively). The results indicate that feeding renders the stomach less susceptible to pharmacologically induced dysrhythmia. However, characteristics of gastric dysrhythmias, such as site of origin and direction of propagation, were similar whether they occurred during fasting or after feeding.

Specific stimulation of simian virus 40 late transcription in vitro by a cellular factor binding the simian virus 40 21-base-pair repeat promoter element

We have identified a cellular transcription factor from uninfected HeLa cells that stimulates the simian virus 40 (SV40) late mode of transcription and specifically binds the SV40 21-base-pair repeat promoter element. In particular, the late SV40 transcription factor (LSF) stimulates transcription at initiation sites L325 and L264 of the SV40 late promoter, which are the major transcription sites utilized after DNA replication during the SV40 lytic cycle. In addition, LSF appears to stimulate transcription to a lesser extent from the late-early initiation site of the early promoter. LSF binds specifically to the 21-base-pair repeats of the SV40 promoters, forming specific protein-DNA complexes, which migrate more rapidly through nondenaturing polyacrylamide gels than that formed by the previously identified transcription factor Sp1. Thus, LSF is distinguishable from Sp1 in both its transcriptional and DNA-binding properties. These findings suggest a potential role of LSF in the early to late transcriptional switch during a SV40 lytic infection.

The nifA gene of Rhizobium meliloti is oxygen regulated

Experiments using plasmid-borne gene fusions and direct RNA measurements have revealed that expression from the nifA gene is induced in Rhizobium meliloti when the external oxygen concentration is reduced to microaerobic levels. Induction occurs in the absence of alfalfa and in the presence of fixed nitrogen and does not require ntrC. The production of functional nifA gene product (NifA) can be demonstrated by its ability to activate the nitrogenase promoter P1. Aerobic induction of nifA can also occur during nitrogen starvation at low pH, but in this case induction is dependent on ntrC and does not lead to P1 activation. The data indicate that reduced oxygen tension is potentially a major trigger for symbiotic activation of nitrogen fixation in Rhizobium species.

Role of the hinge protein in the electron transfer between cardiac cytochrome c1 and c. Equilibrium constants and kinetic probes

A role of the hinge protein is studied in the electron transfer reaction between cytochromes c1 and c, using highly purified "one-band" cytochrome c1 and "two-band" cytochrome c1. The results show that the hinge protein (Hp), which is essential for a stable ionic strength-sensitive c1-Hp-c complex, seems to play a certain role in electron transfer between cytochromes c1 and c; Keq for electron transfer reaction between cytochromes c1 and c in the presence of the hinge protein is found to be about 40% higher than that in the absence of the hinge protein at low ionic strength, but no difference exists at high ionic strength. We propose a hypothesis that the hinge protein may function as regulator for the electron transfer reaction between cytochromes c1 and c, and this may be at least one of the roles of the hinge protein in mitochondria.

Potential anti-AIDS drugs. 2',3'-Dideoxycytidine analogues

5-Substituted 2',3'-dideoxycytidine analogues have been synthesized and evaluated in vitro for their capabilities to protect T4+ lymphocytes from the cytopathic effects of the HTLV-III/LAV (HIV) virus, the causative agent of acquired immunodeficiency syndrome (AIDS). These analogues were designed to be more lipophilic than 2',3'-dideoxycytidine (ddC) in order to enhance central nervous system penetration. Earlier reports had shown that ddC is a potent protective agent. When ddC is substituted at the 5-position with either methyl or bromo substituents, activity is completely abolished. However, when the substitution is fluoro (5-F-ddC), both activity and potency are retained. 2',3'-Dideoxy-5-azacytidine is also protective but more toxic than ddC or 5-F-ddC. In a different approach, an attempt was made to utilize ddCMP, ddTMP, and ddAMP as preformed nucleotides in order to circumvent the generally low level of phosphorylation achieved with dideoxynucleosides which function as relatively poor substrates for the cellular kinases. Only ddAMP is as active as its nucleoside precursor. Because ddAMP is not more active than ddA at low concentrations, it is possible that the active agent is ddA which is generated from ddAMP prior to cell entry.