Quantitative analysis of mutually competitive binding of human Raf-1 and yeast adenylyl cyclase to Ras proteins

Ras proteins appear to have two distinct downstream effectors, adenylyl cyclase in Saccharomyces cerevisiae and a product of raf-1 protooncogene in higher organisms. We found that in vitro activation of adenylyl cyclase by yeast Ras2 and human H-Ras proteins is subject to competitive inhibition by its leucine-rich repeats domain and by the N-terminal regulatory domain of human Raf-1 protein. Kinetic analyses of the inhibition patterns enabled us to determine exact dissociation constants (Kd) of the two polypeptides for Ras2 and H-Ras. The leucine-rich repeats domain bound to the posttranslationally modified Ras2 with the Kd of approximately 13 nM, which was close to the value (7 nM) of the whole adenylyl cyclase. The Kd of Raf-1 for the modified H-Ras, 3.5 nM, was significantly lower than that for Ras2, 24 nM, whereas adenylyl cyclase bound preferentially to Ras2. Similar inhibition was also observed in vivo by suppression of RAS2Val-19-dependent heat shock sensitivity and of Ras-dependent cAMP response to glucose upon overexpression of Raf-1 in yeast. These results indicate that the leucine-rich repeats domain contains the Ras protein-binding site and that Raf-1 and adenylyl cyclase, sharing no structural homology with each other, bind to a similar, if not identical, region of Ras with comparable affinities.

Synthetic oligonucleotides with certain palindromes stimulate interferon production of human peripheral blood lymphocytes in vitro

We studied the ability of synthetic single-stranded 30-mer oligodeoxyribonucleotides (oligoDNAs) with three different kinds of hexamer palindromic sequence to induce interferon (IFN) production of human peripheral blood lymphocytes (PBL). When PBL was cultured with oligoDNA having a palindrome of AACGTT or GACGTC, IFN activity was detected by bioassay in the culture fluid after 8 h, and the amount of IFN reached the maximum after 18 h. IFN-alpha was predominantly produced, and small amounts of IFN-beta and IFN-gamma were also found. OligoDNA with the palindrome ACCGGT had no effect.

Exercise training in a patient with congestive heart failure on continuous dobutamine

We present a 53-yr-old man with congestive heart failure who underwent 32 wk of exercise training. The patient was on a continuous infusion of dobutamine for 10 months prior to exercise training, which was subsequently discontinued at wk 24 of exercise training. Symptom-limited graded exercise tests were performed at baseline, wk 12, wk 24, and wk 32 of exercise training. While on a continuous infusion of dobutamine, the patient's oxygen consumption and exercise duration were increased during the exercise training period. Additionally, the patient was able to maintain these changes for 8 wk while continuing to exercise after the discontinuation of the dobutamine therapy.

[Usefulness of Dornier MPL9000 lithotriptor with new optional fluoroscopic guiding system (electrode X 155: depth 15.5cm) in treatment of urinary tract stone]

The Dornier MPL9000 lithotriptor was originally equipped with an ultrasound guiding system. Recently an optional fluoroscopic guiding system was developed to overcome the known disadvantages of the ultrasound system and to exploit the merits of both systems by using them in combination. Herein, we examined the effectiveness and safety of this new optional system. From December 1990 to February 1991, we treated 41 patients with upper urinary tract stones with MPL9000 using the optional fluoroscopic system. Treatments were judged as effective if the patients were stone-free or the residual fragments were smaller than 4mm in diameter. The overall effectiveness rates at one month after the treatment were 54.5% for renal stones and 76.9% for ureter stones respectively. At three months after the treatment the effectiveness rate for renal stones was 83.3%, and that for ureter stones 95.5%. The changes in the laboratory data after the treatment were alight and caused no clinical problems. Complications during and after the treatment were also minor and tolerable. MPL9000 was sufficiently effective and safe in the treatment of upper urinary tract stones when it was used the new optional fluoroscopic system instead of the original ultrasonic guiding system.

Cardiovascular responses to submaximal arm and leg exercise in cardiac transplant patients

We examined whether an increase in stroke volume (SV) contributes to the increase in cardiac output that occurs when cardiac transplant patients (CT) exercise between 50% and 75% of maximum. Upright arm and leg exercise was performed by 13 CT and 10 normal controls. Cardiac output (CO2 rebreathing), expired air, and catecholamine measures were obtained at rest and at 50% and 75% of maximum. From rest to 50% of maximum both normals and CT increased heart rate (HR) and SV during arm and leg exercise. In normals, HR (arm = +17 +/- 2 min-1; leg = +21 +/- 3 min-1) was increased further at 75% of maximum but not SV (arm = 3 +/- 4 ml; leg = +2 +/- 8 ml). In CT, further increases in both HR (arm = +9 +/- 1 min-1; leg = +13 +/- 1 min-1) and SV (arm = +12 +/- 5 ml; leg = +12 +/- 3 ml) were observed at 75% of maximum. During leg exercise plasma norepinephrine was increased more in CT than in normals. Between 50% and 75% of maximum, an increase in SV is a more important mechanism for increasing cardiac output during upright arm and leg exercise in CT than in normals.

Ability of oligonucleotides with certain palindromes to induce interferon production and augment natural killer cell activity is associated with their base length

A synthetic 30-mer single-stranded oligodeoxyribonucleotide with a hexamer palindrome, AACGTT, induced IFN production and augmented NK activity in murine splenocytes. This effect does not appear to result from an antisense mechanism but rather is due to the palindrome. To clarify the required minimal size of the nucleotide, 10 kinds of 12- to 30-mer nucleotides were examined. Immunostimulatory activity of oligonucleotides 18 bases or more in length was observed and was proportional to the base length, with a maximum of 22-30 bases. On the other hand, the oligonucleotides 16 bases or less in length were not active even if they possessed the palindromic sequence. These results indicate that the immunostimulatory activity of oligonucleotides with certain palindromic sequences requires an oligonucleotide at least 18 bases long.

Cardiovascular responses of cardiac transplant patients to arm and leg exercise

This investigation compares the cardiovascular responses of normal (n = 10) and cardiac transplant (n = 14) subjects to peak arm and leg exercise. It also tests the hypothesis that the higher heart rate (fc) in normal subjects during light (30 W) submaximal arm versus leg exercise is due to cardiac innervation. In cardiac transplant patients, power output, oxygen consumption (VO2), fc and rate pressure product were 54%, 28%, 7%, and 8% lower during peak arm than leg exercise, respectively. In normal subjects, power output, VO2, fc and rate pressure product were 61%, 33%, 8%, and 11% lower during peak arm than leg exercise, respectively. In cardiac transplant patients there was no significant difference in absolute fc during submaximal arm and leg exercise. In normal subjects, absolute fc during arm and leg exercise was [mean (SD)] 97 (4) beats.min-1 and 92 (4) beats.min-1, respectively (P = 0.07). Plasma noradrenaline was increased more during arm than leg exercise in both cardiac transplant and normal subjects. Maximal leg testing is useful when determining the capacity of cardiac transplant patients to perform arm work. The higher absolute fc reported by other investigators for normal subjects during submaximal arm versus leg exercise may be mediated by cardiac innervation.

Screening for specific inhibitors of phagocytosis of thioglycollate-elicited macrophages

Phagocytosis is one of the basic and characteristic properties of macrophages. We screened metabolites of Actinomyces for low molecular weight substances that selectively inhibited phagocytosis of dried yeast but not pinocytosis of neutral red by thioglycollate-elicited peritoneal macrophages. Inhibitors of actin filament organization, protein kinases, respiration, and lipid synthesis selectively inhibited phagocytosis, and blockers of proton gradients selectively inhibited pinocytosis. This suggests that these functions are differently regulated. We applied this system to screening of metabolites of Actinomyces, and identified mycotrienin, piericidin, and genistein as selective inhibitors of phagocytosis.

Giant thymolipoma in a child

Thymolipoma, a rare benign mediastinal tumor, was found in a 6-year-old boy. Computed tomography scans, magnetic resonance imaging, and angiography of internal thoracic artery confirmed the diagnosis before surgery.

Effects of the new calcium antagonist monatepil on cardiac function and myocardial oxygen supply and demand in animals

The effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b,e]thiepin-11-yl)-4-(p-fluor ophenyl)-1- piperazinebutyramide]maleate, AJ-2615, CAS 103377-41-9), a new calcium antagonist, on cardiac function and myocardial oxygen supply and demand were examined. 1. Monatepil reduced the spontaneous beats of isolated rabbit atria at the concentration of 3 x 10(-6) and 10(-5) mol/l. Monatepil decreased the contractile force of papillary muscles in a concentration-dependent manner (3 x 10(-8)-10(-5) mol/l). 2. Monatepil (0.3 mg/kg i.v.) slightly decreased heart rate in anesthetized open-chest dogs. This drug (0.1, 0.3 mg/kg i.v.) increased cardiac output and decreased blood pressure and total peripheral resistance. Monatepil decreased left ventricular dP/dtmax and slightly increased left ventricular end-diastolic pressure. 3. Monatepil (0.1-1.0 mg/kg i.v.) did not affect the PR interval, QRS duration and QTc interval of electrocardiograms in anesthetized dogs, whereas diltiazem (0.3 and 1.0 mg/kg i.v.) markedly prolonged the PR interval. 4. Monatepil (0.1-0.3 mg/kg i.v.) increased coronary blood flow (CoBF) and decreased myocardial oxygen consumption (MOC) and extraction. 5. Monatepil and diltiazem showed almost the same effects on cardiac function and myocardial oxygen supply and demand, but the negative chronotropic and negative dromotropic effects of monatepil were less potent than those of diltiazem.

Detection of minimal residual disease in Philadelphia chromosome positive acute lymphoblastic leukemia: rationale for bone marrow transplantation from the polymerase chain reaction point of view

Bone marrow transplantation (BMT) is performed as curative therapy for acute lymphoblastic leukemia (ALL). In most patients, BMT is performed at the time of remission which implies that the number of leukemic cells is less than 5% of all hematopoietic cells, namely, 0 to 10(10) leukemia cells in the body. Thus, some patients may well undergo BMT despite the fact that no leukemic cells are left in the body. In this respect, more accurate diagnosis of complete remission status would be to the patients' benefit. To detect minimal residual disease (MRD) not found by light-microscopy, further strategies are required after achieving hematological remission. Cytogenetic methods, Southern blot analysis and conventional immunological techniques can all provide accurate diagnosis, however, the sensitivity of these techniques for the detection of MRD is just as low as that of the light microscopy. Recently, polymerase chain reaction (PCR) has become available for the detection of low levels of chimeric bcr-abl transcripts in Philadelphia chromosome positive (Ph1) ALL patients. With this assay, investigators have reported MRD in patients after chemotherapy or BMT. Most patients who achieve hematological remission after conventional chemotherapy still have bcr-abl transcript detectable by PCR, confirming the general concept that this particular leukemia needs BMT in order to cure the disease. Some patients who had MRD prior to BMT continued disease free survival > 1 year after BMT with a negative PCR result and in these patients, MRD seems to have been eradicated by the BMT procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

Fully methylated oriC with negative superhelicity forms an oriC-membrane complex before initiation of chromosome replication

In an in vitro assay, the oriC DNA has been shown to bind to the outer membrane fraction only when it is hemimethylated (G.B. Ogden et al., Cell, 54, 127-135,1988). In this report, however, we demonstrated that a significant amount of the oriC DNA was recovered from the cells just before initiation with the oriC DNA being fully methylated. Formation of this preinitiation oriC-membrane complex and following initiation of chromosome replication were strongly inhibited by novobiocin, a DNA gyrase B subunit inhibitor, which reduced the superhelicity of the reporter plasmid in the cells. On the other hand, both reactions proceeded in the presence of nalidixic acid, a DNA gyrase A subunit inhibitor, which did not have the effect of reducing the superhelicity. These results suggest that the negative superhelicity of the DNA is required for preinitiation oriC-membrane complex formation and following initiation event of replication.

In vitro and in vivo electrocardiographic evaluation of the novel calcium antagonist monatepil on cardiac conduction system

Effects of monatepil ([(+/-)-N-(6,11-dihydrodibenzo[b, e]thiepin-11-yl)-4-(p-fluorophenyl)-1-piperazinebutyramide]m aleate, AJ-2615, CAS 103377-41-9), a novel calcium antagonist, on the cardiac conduction system were compared by electrocardiography with those of the existing calcium antagonists (diltiazem, verapamil and nifedipine) in isolated rabbit heart preparations in vitro and in anesthetized and conscious dogs in vivo. Monatepil (10(-7) mol/l) prolonged the atrio-His bundle conduction time (AH interval) in the Langendorff perfused rabbit heart, like diltiazem, verapamil and nifedipine. This prolongation was decreased to 1/10 in the presence of 3.6% bovine serum albumin. In anesthetized dogs, monatepil (0.1-1.0 mg/kg i.v.), unlike diltiazem and verapamil, did not prolong AH interval. In conscious dogs, monatepil even at 100 mg/kg p.o. did not affect electrocardiograms. At the high dose of 300 mg/kg p.o., only a slight prolongation of the QT interval was found, but the QTc interval was not affected. Diltiazem at 10 mg/kg p.o. caused a prolongation of the PR interval and a disappearance of QRS waves. In conscious renal hypertensive dogs, repeated administration of monatepil (10 mg/kg/d p.o. for 29 days) had little effect on the conduction system of the heart examined by electrocardiograms, albeit a persistent fall in blood pressure continued throughout the administration period. The above results suggest that monatepil is a highly safe drug in the treatment of hypertension.

Analysis of the function of the 70-kilodalton cyclase-associated protein (CAP) by using mutants of yeast adenylyl cyclase defective in CAP binding

In Saccharomyces cerevisiae, adenylyl cyclase forms a complex with the 70-kDa cyclase-associated protein (CAP). By in vitro mutagenesis, we assigned a CAP-binding site of adenylyl cyclase to a small segment near its C terminus and created mutants which lost the ability to bind CAP. CAP binding was assessed first by observing the ability of the overproduced C-terminal 150 residues of adenylyl cyclase to sequester CAP, thereby suppressing the heat shock sensitivity of yeast cells bearing the activated RAS2 gene (RAS2Val-19), and then by immunoprecipitability of adenylyl cyclase activity with anti-CAP antibody and by direct measurement of the amount of CAP bound. Yeast cells whose chromosomal adenylyl cyclase genes were replaced by the CAP-nonbinding mutants possessed adenylyl cyclase activity fully responsive to RAS2 protein in vitro. However, they did not exhibit sensitivity to heat shock in the RAS2Val-19 background. When glucose-induced accumulation of cyclic AMP (cAMP) was measured in these mutants carrying RAS2Val-19, a rapid transient rise indistinguishable from that of wild-type cells was observed and a high peak level and following persistent elevation of the cAMP concentration characteristic of RAS2Val-19 were abolished. In contrast, in the wild-type RAS2 background, similar cyclase gene replacement did not affect the glucose-induced cAMP response. These results suggest that the association with CAP, although not involved in the in vivo response to the wild-type RAS2 protein, is somehow required for the exaggerated response of adenylyl cyclase to activated RAS2.

Multiple binding modes for the receptor-bound conformations of cyclic AII agonists

Angiotensin II, Asp-Arg-Val-Tyr-His-Pro-Phe, binds its receptor with a postulated turn centered at residue four. Analogs of angiotensin II which contain a disulfide bridge between the side chains of residues 3 and 5 retain significant activity consistent with this hypothesis. Incorporation of 4-mercaptoproline residues, a hybrid, or chimeric amino acid which combines the properties of proline and homocysteine, into either of these positions with analogous disulfide bridges allows retention of high affinity for the receptor. These more highly constrained bicyclic systems give new insight into the details of molecular recognition of residues 3-5 of angiotensin by the receptor. Retention of activity by the antiparallel dimer of [Sar1,Cys3,5]-AII in which the peptide backbone is held in an extended conformation was unexpected. Analysis of the conformational constraints imposed in these active analogs suggests that AII agonists bind to their receptor with different backbone conformations in the region of the central tyrosine residue.

Melastin, a novel product of Streptomyces that selectively inhibits leukemia cell growth

In the course of our screening for new immunomodulators, a novel compound, melastin, was purified from the culture broth of Streptomyces. Melastin was purified through absorption to Diaion HP-20, ethanol precipitation, and anion exchange column as a brown powder. The molecular weight was estimated as 5000 +/- 3000 by gel filtration HPLC. Melastin suppressed lipopolysaccharide (LPS)-induced blastogenesis of B cells more profoundly than concanavalin A (con A)- or phytohemagglutinin (PHA)-induced blastogenesis of T cells. Moreover, it selectively inhibited the growth of several leukemia cells as compared with interleukin-dependent nontransformed leukocytes. No selectivity was observed between nontransformed fibroblasts and their oncogene-transformed variants. Melastin did not selectively inhibit macromolecule synthesis of leukemia cells.

[Tuberculin sensitivity to purified protein derivatives from Mycobacterium other than tuberculosis (PPD-B, PPD-Y, PPD-F and PPD-C) and PPDs among patients with mycobacteriosis--cooperative study of the Research Committee for the Mycobacteriosis in Japan]

Purified protein derivatives (PPDs) prepared from M. intracellulare (PPD-B), M. kansasii (PPD-Y), M. fortuitum (PPD-F), M. chelonei subsp. abscessus (PPD-C) and M. tuberculosis (PPDs) were simultaneously used in skin tests on patients diagnosed as having tuberculosis or atypical mycobacteriosis to reveal their specificity, clinical usefulness and immunological status of the patients. The mean diameter of reaction (redness) for patients with M. tuberculosis positive sputum (TB group, n = 71; age, 20-90 yrs) was PPDs, 20.4 mm; PPD-B, 7.9 mm; PPD-Y, 11.7 mm; PPD-F, 0.8 mm; and PPD-C, 0.3 mm. For M. avium complex positive patients (MAC group, n = 100; age, 31-89 yrs), the results were PPDs, 10.9; PPD-B, 16.9 mm; PPD-Y, 10.7 mm; PPD-F, 1.6 mm; and PPD-C, 0.3 mm. The M. kansasii positive patients (K group; n = 8) showed results of PPDs, 12.6 mm; PPD-B, 10.7 mm; PPD-Y, 20.8 mm; PPD-F, 0.5 mm; PPD-C, 0.0 mm. The M. fortuitum positive patients (F group; n = 5) had measurements of PPDs, 5.8 mm; PPD-B, 4.4 mm; PPD-Y, 9.8 mm; PPD-F, 17.8 mm; and PPD-C, 16.0 mm. The patients who were previously M. tbc. positive but presently negative patients (pre. TB group; n = 50) showed the following results: PPDs, 16.6 mm; PPD-B, 7.4 mm; and PPD-Y, 10.9 mm. For the patients who were previously M. avium complex positive (previous MAC group; n = 19), the results were PPDs, 10.4 mm; PPD-B, 9.9 mm; and PPD-Y, 7.7 mm. Also considering their frequency distribution curve, with exception of the previous MAC group, the patient groups showed specificity to the PPD of the bacilli detected. The previous MAC group recorded no significant difference in response to PPDs and PPD-B. Strong cross reactions were observed between PPD-F and PPD-C, and moderate reactions between PPDs, PPD-B and PPD-Y. Cross reactions were scarce between PPDs, PPD-B or PPD-Y and PPD-F or PPD-C. Though it is difficult to distinguish cross-reaction and multiple infections, majority of the patients (72-85%) showed greatest response to the PPD that corresponds with the species of bacilli detected. In conclusion, two or more PPDs applied simultaneously can be of aid in diagnosing mycobacteriosis especially in the early stages of the disease. Also, cross-reactions between atypical mycobacteria and PPDs should be taken into consideration when diagnosing infection caused by M. tuberculosis.

[Changes in renal blood flow after treatment with ESWL in patients with renal stones. Studies using ultrasound color Doppler method]

Recently several authors have observed tissue damages in ESWL treated kidneys, such as interstitial hemorrhage and edema, cavitation of renal tubular cells and vascular spasms. Examination using renal scintigraphy suggested that these damages could cause a decrease of renal blood flow in the treated kidney. Trying to confirm and further investigate this possibility, we studied on changes of renal blood flow velocity using ultrasound color doppler method in 23 consecutive patients with renal stones who underwent ESWL. The studies were conducted before, immediately after and 1 week after an ESWL treatment. Results were as follows; renal blood flow velocity decreased significantly in the area exposed to shock were immediately after the treatment and returned to the pretreatment levels after 1 week. The changes were not significant in the non-exposed area. In parallel with this decrease of renal blood flow velocity, significant increases of resistive index, pulsatility index and significant decreases of ratio were observed. These parameters calculated by measuring of renal blood flow velocity are known to well correlate with parenchymal vascular resistance. We speculate that these changes in renal parenchymal blood flow velocity are triggered by the tissue damages caused by the exposure to shock wave. The recovery of renal blood flow velocity may depend on the recovery of the tissue damages. Ultrasound color doppler method may make it possible to monitor the recovery of tissue damages induced by shock wave and may provide us with an useful information to determine when to repeat ESWL if needed.