Dual regulation by G proteins of agonist-dependent phosphorylation of muscarinic acetylcholine receptors

Muscarinic acetylcholine receptors purified from porcine atrium were phosphorylated, depending on the presence of agonists, by a protein kinase partially purified from porcine brain, which had similar properties to the beta-adrenergic receptor kinase. GTP-binding regulatory proteins (Go) had dual effects on the phosphorylation of muscarinic receptors, i.e. stimulation at lower concentrations and inhibition at higher concentrations. The stimulatory effect was reproduced with the beta gamma subunit of Go and the inhibitory effect with the combination of the alpha and beta gamma subunits.

Molecular analysis of structural protein genes of the Yamagata-1 strain of defective subacute sclerosing panencephalitis virus. IV. Nucleotide sequence of the fusion gene

The full-length cDNA corresponding to the mRNA of the fusion (F) protein of the Yamagata-1 strain of subacute sclerosing panencephalitis (SSPE) virus was cloned, and its complete nucleotide sequence was determined. The F gene was composed of 2369 nucleotides and contained a single large coding region, which is located between two noncoding regions. The 5'-terminal noncoding region consisted of 584 nucleotides comprising 44.9% cytosine, and had several inverted repetitious sequences. The 3'-terminal noncoding region had a relatively low homology of 91.7% with the MV. The coding region was expanded for nucleotides 585-2189, which encoded 534 amino acids with a molecular weight of 57,963. The homology of the amino acid sequence of the F protein between the MV and SSPE virus was 96.27%, and the positions of cysteine and proline were almost identical in the two viruses. The functional domains of SSPE-virus F protein closely resembled those of MV F protein, including the cleavage site, a signal sequence, the fusion-related stretch, the transmembrane region, and four potential glycosylation sites. Four antigenic epitopes on the MV F protein were also conserved on the SSPE-virus F protein. However, deletion of one nucleotide (position 2155) of the SSPE virus was found when compared with the MV, and shifted the coding frame, causing the substitutions of 27 C-terminal amino acids of the MV F protein with 11 different residues. The variations of the C-terminal region of the F protein were observed with two other SSPE viruses, suggesting that this may be a common property of SSPE virus that differs from MV.

Molecular analysis of structural protein genes of the Yamagata-1 strain of defective subacute sclerosing panencephalitis virus. III. Nucleotide sequence of the hemagglutinin gene

The full-length cDNA corresponding to the mRNA for the hemagglutinin (H) protein of the Yamagata-1 strain of the subacute sclerosing panencephalitis (SSPE) virus was cloned and the nucleotide sequence was determined. The mRNA corresponding to the H protein was composed of 1952 nucleotides and contained a single large open reading frame, which encoded 620 amino acids with a predicted molecular weight of 69,723. This cDNA clone expressed the H protein in Cos 7 cells, and the transfected cells showed hemadsorption. The nucleotide and amino-acid sequence homology with the Edmonston strain of MV were 98.0% and 96.6%, respectively. The deduced amino acid sequence had a single hydrophobic domain near the N-terminus that was long enough to serve as an anchor in the membrane. Five potential glycosylation sites were found on the H protein at identical positions as in the H protein of MV. Cysteine and proline were located at almost identical positions as those of the H protein of MV. In addition, monoclonal antibody study revealed that three epitopes, including the domains that were involved in the biological activities of the H protein of MV, were conserved on the Yamagata-1 strain. These results suggested that the H protein of the Yamagata-1 strain of defective SSPE virus is structurally and functionally similar to that of the Edmonston strain of MV.

Molecular analysis of structural protein genes of the Yamagata-1 strain of defective subacute sclerosing panencephalitis virus. II. Nucleotide sequence of a cDNA corresponding to the P plus M dicistronic mRNA

The nucleotide sequence of a cloned cDNA corresponding to the P + M dicistronic mRNA of a subacute sclerosing panencephalitis (SSPE) virus was determined and compared with data of measles virus (MV). The dicistronic mRNA of the SSPE virus consisted of the 3' proximal 626 nucleotides of P mRNA, intercistronic trinucleotides, a full length of M mRNA, and 75 poly A nucleotides. The part encoding the P protein had a high homology to MV, except at the noncoding region. The terminating consensus sequence of the P gene and the intercistronic trinucleotides of the SSPE virus were CTAC(A)6 and CCT; in MV they are TTAT(A)6 and CTT, respectively. In the M gene, the starting consensus sequence was exactly the same as MV, but at the 5' proximal end, one third of this gene was different: The first ATG codon of the MV M gene signaling opening of the reading frame was changed to ACG in the SSPE virus and one long open reading frame started from the third ATG codon. The stop codon (TAG) of the MV M gene was also changed to CAG in the SSPE virus. Thus, the deduced SSPE-virus M protein lacked 50 amino acids at the amino terminal and had 15 extra amino acids at the carboxyl end when compared with the MV M protein.

[Effects of immunoglobulin preparations on the opsonic activities against various pathogens]

We evaluated the opsonic activities of human intravenous immunoglobulin (IVIG) preparations against pathogenic organisms by measuring the luminol-enhanced chemiluminescence (CL) from human polymorphonuclear leukocytes (PMN) during the phagocytosis of these organisms. Polyethylenglycol-treated IVIG significantly increased the CL of PMN by opsonization against various bacteria and Candida albicans (p less than 0.01). The high CL induced by IVIG with intact Fc-fragment showed no significant differences among lots or preparations made by different treatments. In both PMN-CL in the absence of human serum and whole blood CL at low concentration of serum complement, the CL response was not affected by pepsin-treated IVIG. In the severely burned patients' blood with a very low concentration of serum immunoglobulin, IVIG with intact Fc-fragment significantly increased CL (p less than 0.01). It is suggested that administration of IVIG is useful against infections in these patients. The measurement of whole blood CL in vitro may be useful for evaluating the opsonic activity of IVIG against target pathogens in vivo.

Diversity of matrix protein in subacute sclerosing panencephalitis and measles virus-infected cells

Expression of the viral matrix (M) proteins in Vero cells infected with 18 strains of subacute sclerosing panencephalitis (SSPE) virus and measles virus was examined by immunocytochemistry and Western blot analysis using an anti-M monospecific serum and two sera against the M protein specific synthetic peptides. By immunocytochemistry using the anti-M monospecific serum, M protein was detected in all of the virus-infected cells regardless of cell-free virus production. M proteins of the seven non-productive strains were found to vary significantly in their epitope, in their reactivity to different assay systems, and in their molecular weight, whereas M proteins of the other 11 productive strains were detected consistently. These results suggest diversification of M protein of the non-productive strains.

Location in muscarinic acetylcholine receptors of sites for [3H]propylbenzilylcholine mustard binding and for phosphorylation with protein kinase C

Muscarinic acetylcholine receptors purified from porcine cerebra or atria were covalently labeled with [3H]propylbenzilylcholine mustard ([3H]PrBCM), and then the labeled receptors were subjected to limited hydrolysis with trypsin, V8 protease, and lysyl endopeptidase, followed by analysis involving sodium dodecyl sulfate-polyacrylamide gel electrophoresis, fluorography, autoradiography, or immunostaining. The labeled peptides were located on the basis of their reactivity with antibodies raised against three synthetic peptides with partial sequences of the m1 or m2 receptor, and of their sensitivity to endoglycosidase F, which was taken as evidence that they contain glycosylation sites near the N terminus. The [3H]PrBCM-binding site in both cerebral and atrial receptors was found to be located between the N terminus and the second intracellular loop, because the size of the smallest deglycosylated peptide that contained both the [3H]PrBCM-binding and glycosylation sites was approximately 16 kDa. Cerebral receptors were 32P-phosphorylated with protein kinase C, and the major phosphorylation sites in cerebral muscarinic receptors were found to be located in a C-terminal segment including a part of the third intracellular loop, because a 32P-labeled peptide of 12-14 kDa reacted with anti-(m1 C-terminal peptide) antiserum. The presence of an intramolecular disulfide bond, probably between Cys 98 and Cys 178 in the first and second extracellular loops, respectively, was suggested by the finding that a peptide of approximately 17 kDa containing the [3H]PrBCM-binding site, but not the glycosylation sites, was partly converted to a peptide of approximately 12 kDa on treatment with beta-mercaptoethanol.

Phosphorylation by protein kinase C of the muscarinic acetylcholine receptor

Muscarinic acetylcholine receptors purified from porcine cerebrum were phosphorylated by protein kinase C purified from the same tissue. More than 1 mol of phosphate was incorporated per mole of receptor, with both serine and threonine residues being phosphorylated. Neither the degree nor the rate of the phosphorylation was affected by the presence or absence of acetylcholine. GTP-sensitive high-affinity binding with acetylcholine was observed for muscarinic receptors reconstituted with GTP-binding proteins (Gi or Go), irrespective of whether muscarinic receptors or the GTP-binding proteins had been phosphorylated by protein kinase C or not. This indicates that the interaction between purified muscarinic receptors and purified GTP-binding proteins in vitro is not affected by their phosphorylation.

Carbachol-induced potentiation and inhibition of acid secretion by guinea pig gastric gland

The effects of muscarinic ligands on acid secretion were examined by estimating the accumulation of [14C]aminopyrine in gastric glands isolated from guinea pigs. The accumulation of [14C]aminopyrine in the presence of 0.1 mM histamine was potentiated by 1 microM carbachol but suppressed by 1 mM. These two effects of carbachol were abolished by atropine, pirenzepine and AF-DX 116. Assuming that the binding of carbachol to one site (Site 1) increases [14C]aminopyrine accumulation but its binding to the other site (Site 2) reduces [14C]aminopyrine accumulation, we analysed the dose-response curves for the carbachol effects in the absence and presence of different concentrations of atropine, pirenzepine and AF-DX 116. The dissociation constants determined for these ligands at Sites 1 and 2 were as follows: carbachol, 0.28 and 7.1 microM; atropine, 0.28 and 0.54 nM; pirenzepine, 45 and 560 nM; and AF-DX 116, 380 and 4400 nM, respectively. The binding of [3H]N-methylscopolamine to the gastric glands indicated the presence of two populations of binding sites with different affinities for the above ligands, other than atropine. The apparent dissociation constants, which were estimated by analysing the displacement curves for [3H]N-methylscopolamine binding, were as follows: carbachol, 0.18 microM (10%) and 31 microM (90%); atropine, 1.24 nM; pirenzepine, 15 nM (16%) and 220 nM (84%); and AF-DX 116, 370 nM (10%) and 2970 nM (90%). These results suggest that there are two kinds of muscarinic acetylcholine receptors in the guinea pig gastric gland, one potentiating and the other inhibiting the acid secretion induced by histamine.

[The present aspect of tuberculous pleurisy--report of the 29th series (A) of CSUCT--Cooperative Study Unit of Chemotherapy of Tuberculosis (CSUCT) of the National Sanatoria in Japan]

CSUCT carried out 9-21 month's follow up of 273 patients with exudative tuberculous pleurisy who were admitted to 39 national sanatoria in 1985, and were treated for the first time. The background factors of the patients at the time of admission were as follows: the average age, 47.2; male/female ratio 3:1; idiopathic pleurisy 163 cases and secondary pleurisy 110 cases. Distribution of maximal temperature on admission; 37.0 degrees C or less 24.4%; 37.1-38.0 degrees C 37.8%; 38.1-39.0 degrees C 28.5%; higher than 39.0 degrees C 9.3%. Younger patients tended to show higher temperature than the older. The positivity of tuberculin reaction was 84.3%, and among them 34% were strongly positive (greater than or equal to 20 mm). There was no correlation between the volume of pleural effusion and the intensity of tuberculin reaction. In patients more than 60 years of ages, the positivity was low (76.0%). The erythrocyte sedimentation rate (after 1 hour) was 63.6 +/- 31.6 mm.

CLINICAL SYMPTOMS

cough in 72%; sputum in 48.5%; chest pain in 57.5%; tubercle bacilli in sputum in 11.6%. We compared idiopathic pleurisy (I) and secondary pleurisy (S) and total cases of pleurisy (T) regarding several factors; average age (I: 46.7, S: 48.0, T: 47.2); peak season of incidence (I: Feb. Mar. S: Mar. April, T: Feb. Mar. April); the period of hospitalisation (I: 4.07 months, S: 5.80 months, T: 4.77 months); the positive rate of tubercle bacilli in the pleural effusion (I: 9.0%, S: 12.9%, T: 10.5%); %VC (mean value) on admission (I: 71.4%, S: 69.8%, T: 70.7 +/- 17.0%); %VC after treatment (I: 79.0%, S: 79.7%, T: 79.4 +/- 17.9%), and we found no significant difference in the above factors between I. and S. In 49 patients who were treated by chemotherapy with steroids, %VC before treatment was 68.9% (mean value), and that after treatment was 81.2% (mean value), however, there was no significant difference between the %VC of these patients and that of total patients. Recent chemotherapy (SM or EB + INH + RFP) greatly contributed to improve clinical symptoms by accelerating the absorption of pleural effusion and in minimizing the formation of pleural thickening. Previously, we experienced often deterioration of tuberculous lesions in relation to the use of steroids. By the use of recent intensified chemotherapy, the harmful side effects of steroids became almost insignificant, and at the same time, treatment with steroids is needed only in a few cases.

Interaction of atrial muscarinic receptors with three kinds of GTP-binding proteins

Purified porcine atrial muscarinic acetylcholine receptors were reconstituted into lipid vesicles with three different G proteins (Gi, Go and Gn)1 purified from porcine cerebrum. All the G proteins interacted with the receptor as evidenced by GTP-sensitive high affinity binding with acetylcholine, and stimulation by acetylcholine of GTP gamma S binding and GTPase activities. The curves of displacement by acetylcholine of [3H]QNB binding were explained by assuming two sites with the same affinity for [3H]QNB but different affinities for acetylcholine. The proportion of the high affinity site increased from 3 to 7% up to 82 to 83% of total binding sites with increasing G protein concentration, and essentially the same results were obtained with the three G proteins. The GTPase activities of Gi, Go and Gn in the reconstituted vesicles were 2.7-, 1.7- and 1.6-times higher, respectively, in the presence of 1 mM acetylcholine than those in the presence of 10 microM atropine. An obvious enhancement by acetylcholine of the GTP gamma S binding was observed in the presence of 10 to 100 microM GDP, while the enhancement was minimal, if at all, in the absence of GDP. When the molar ratios of reconstituted Gi, Go and Gn to muscarinic receptors were 54, 84 and 107, respectively, the acetylcholine-induced increase in the [35S]GTP gamma S binding was as much as 12, 35 and 27 mol with Gi, Go and Gn, respectively, per mole of the receptor molecule, indicating that the muscarinic receptors interact with G proteins catalytically.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of the lipid environment on the differential affinity of purified cerebral and atrial muscarinic acetylcholine receptors for pirenzepine

Muscarinic acetylcholine receptors (mAChRs) of porcine cerebral membrane (predominantly M1 subtype) and porcine atrial membrane (M2 subtype) showed the same affinity for the muscarinic antagonist [3H]quinuclidinylbenzylate [( 3H]QNB). In contrast, the affinity for pirenzepine (another muscarinic antagonist) of 86% of binding sites in the cerebral membrane (H sites) was 34-fold higher than that in the atrial membrane. After purification of mAChRs by affinity chromatography, this difference was less than 3-fold. This phenomenon was fully reversed by insertion of purified mAChRs into either cerebral or atrial membranes whose native muscarinic binding sites had been alkylated with propylbenzilycholine mustard, indicating that the purified receptors recovered their original affinities for pirenzepine upon interaction with membrane components. To examine the effect of the interaction between receptors and lipid components on the affinities for [3H]QNB and pirenzepine, binding experiments were carried out with mAChRs inserted into various lipid preparations. When purified cerebral and atrial mAChRs were inserted into cholesteryl hemisuccinate, their affinities for [3H]QNB and pirenzepine became close to the membrane values and were 7- and 50- to 60-fold higher than those of receptors inserted into phosphatidylcholine, respectively. When insertion was carried out into either cholesteryl hemisuccinate, phosphatidylcholine, or cholesteryl hemisuccinate/phosphatidylcholine mixtures, (80:20 and 50:50, w/w), the affinity of cerebral H sites for pirenzepine was only 3- to 5-fold higher than that of atrial receptors, but it became 20- and 60-fold higher when the receptors were inserted in a cholesteryl hemisuccinate/phosphatidylcholine mixture (20:80, w/w) and in a cholesteryl hemisuccinate/phosphatidylcholine/phosphatidylinositol mixture (4:48:48, w/w), respectively. These results suggest that the affinities of mAChRs for antagonists, in particular the differential affinities of cerebral and atrial mAChRs for pirenzepine, are modulated by the lipid environment.

[A case of septic shock due to pneumonia caused by Klebsiella pneumoniae]

A 51-year-old male, who had a history of excessive drinking and chronic hepatitis, was admitted to our hospital because of high fever and shock. Physical examinations, chest X-ray films and hemodynamic data revealed that he had progressed to septic shock due to pneumonia. Combination chemotherapy of latamoxef plus piperacillin was immediately started. After Klebsiella pneumoniae was isolated from bronchoalveolar lavage fluid, the antibiotics were changed to ceftizoxime plus amikacin. Furthermore human gamma globulin preparations and frozen fractional plasma were administered because of granulocytopenia and a decrease in complement. Gabexate mesylate, methylprednisolone (MP) and branched chain amino acids were given to prevent disseminated intravascular coagulation and/or multiple organ failure. With this intensive care, he recovered from shock and pneumonia. The effects of MP on the whole blood chemiluminescence (CL) were examined. Incubation of whole blood with 25, 50 or 100 micrograms/ml of MP for 10 to 60 minutes had no effects on the CL response. This indicates that MP does not affect the production of reactive oxygen species from phagocytic cells at concentrations comparable to those used in drug therapy.

[Cancer treatment in terminal stage]

The decision of treatment for cancer patient in terminal stage differs from that of patients in early stage or in stage of good P.S. (performance status). The small part of patients desire to make every effort for life-prolongation if it follows severe complications, but major part of patients desire to relief from several pains and distresses, or to maintain high quality of life and living. True and enough informations are necessary for patient to choose or decide the course of treatment. The self-decision for treatment by informed consent is desirable. The three points of terminal care are follows: 1) Life-prolonging treatment Life-prolonging treatments with less distress and complication, if that is based on informed consent, are usefull and necessary. 2) Relief for pains and distresses Pain control and aids for psycho-social-religious distresses. 3) Support for the death of desirable choice How to die is how to live. The treatment based on patient's view of life must be chosen. (A) Pre-terminal stage To keep balance the wills for social life and/or life-work and complications of treatment. (B) Final stage The decision of choice of resuscitation and/or intensive care must be decided by patient and/or family.

[Interstitial irradiation of carcinoma of the tongue]

From 1977 to 1988, 61 patients have received radical treatment for a carcinoma of the mobile tongue. Fifty-nine of these patients were treated in association with a BLM (or PEP), and 26 patients with external irradiation. The local tumor control rate at two years was 77%, and subsequent lymph node metastasis was 25%. The five year cumulative survival rate was 55% and the main causes of death were found to be regional node metastases and other related diseases particularly. The determinate survival for TxN0 tumors was 83%. Six percent and 26% had radio-osteonecrosis and soft tissue necrosis respectively and three patients required surgery.

[Hyperamylasemia in acute exacerbation in patients with chronic respiratory failure]

Serum amylase level was examined in 129 cases (225 episodes) of chronic respiratory failure at acute exacerbation, and in 59 cases (62 episodes) of pneumonia without respiratory failure as a control. Cases accompanying diseases, such as acute pancreatitis, parotiditis, ileus, and renal dysfunction, which were expected to develop hyperamylasemia were excluded. The 225 episodes were divided according to the cause of acute exacerbation into 4 groups: pneumonia, bronchitis, right heart failure without infection, and others (e.g. hemoptysis). Hyperamylasemia (greater than 400 S-U) was observed in groups of pneumonia (15/40 = 35.5%) and of bronchitis (12/95 = 12.6%) respectively, but not in those of right heart failure without infection (0/73 = 0%) and others (0/17 = 0%). As a result, hyperamylasemia was found only under conditions of inflammation of lung parenchyma and bronchi with acute exacerbation of respiratory failure. On the other hand no hyperamylasemia was observed in 62 episodes of only pneumonia without respiratory failure. It was concluded that both respiratory tract infection and acute respiratory failure are necessary factors for development of hyperamylasemia originating from lung or bronchi.

Cerebral muscarinic acetylcholine receptors interact with three kinds of GTP-binding proteins in a reconstitution system of purified components

A new GTP-binding protein, which serves as a substrate for pertussis toxin, was prepared from porcine brain. The new G protein was separated from other GTP-binding proteins, Gi and Go, by an anion-exchange column chromatography. The mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the alpha subunit of the new G protein was between those of alpha subunits of Gi and Go. Evidence that the alpha subunit is not a proteolytic fragment of the alpha subunit is not a proteolytic fragment of the alpha subunit of Gi or Go was provided by experiments involving partial hydrolysis of these G proteins with thermolysin and their interaction with an antibody raised against the amino terminal peptide of the alpha subunit of Gi. In addition, the gamma subunit of the new G protein was indicated to be different from the gamma subunits of Gi and Go, because the latter were found to be phosphorylated by protein kinase C but the former was not. GTP-sensitive high affinity binding of muscarinic receptors with acetylcholine was observed when muscarinic receptors purified from porcine cerebrum were reconstituted in phospholipid vesicles with the new G protein as well as with Gi or Go. The proportion of the high affinity sites increased with the concentrations of the G proteins, the potency of the new G protein being similar to that of Gi but a little lower than that of Go. This GTP-sensitive high affinity binding was not observed when each G protein was pretreated with pertussis toxin and then reconstituted with muscarinic receptors. Acetylcholine accelerated the dissociation of [3H]GDP from the new G protein as well as from Gi and Go, which were reconstituted with muscarinic receptors. These results indicate that muscarinic receptors interact with at least the above three kinds of G proteins, in a pertussis toxin-sensitive manner.

[Development and treatment of respiratory failure due to tuberculosis]

Though the incidence, prevalence, and mortality of tuberculosis have decreased so quickly in last thirty years in Japan, we still have many persons suffering from so called tuberculosis sequelae who complain pulmonary symptoms, particularly respiratory failure. As I have been studying this problems for last many years as a part of tuberculosis treatment, I would like to summarize the present status of the problem. 1) Acute respiratory failure is observed in DIC followed by miliary tuberculosis and in far advanced cases. 2) Chronic respiratory failure is common in pulmonary tuberculosis sequelae. Sexual ratio, male to female is three to two and average age is 60.5. It is quite reasonable that advanced restrictive failure, %VC less than 40%, occurs in 70% of all cases, but obstructive disturbance, FEV1.0% less than 55%, was also observed in 40% of cases. It is still not so clear why tuberculosis sequelae shows obstructive ventilatory failure, but the response to obstruction with the administration of beta-stimulant is observed. Advanced hypoxemia, PaO2 less than 50 Torr, is observed in 30% and hypercapnea is observed in 70% of total cases. Clinical right heart disturbance is observed in 80% of cases. 3) Based on to calculation from the number of interval organ failure and questionnaire to hospitals, the number of persons suffering from respiratory failure is estimated at 20 per 100,000, and it is presumed that the prevalence of respiratory failure will begin to decrease in two to five years later. 4) Pulmonary hypertension, mPA 28.8 mmHg, and higher PVR, 402, are observed in 90 catheterized cases. alpha-NA Peptide in serum and ACT, RVET by echocardiogram are well related to the value of mPA. 5) Average accumulated survival rate is 50% after three years, and it related closely with PaO2. 6) Long term oxygen therapy is the most reasonable and practical treatment for not only to increase the life span but also to improve QOL of the patient. Exercise training is also effective. Almitrine (clinical trial base in Japan), Doxopram and other drugs are effective to recover hypoxemia and to improve pulmonary hypertension. Home mechanical ventilation just started in Japan, and two cases for tuberculosis sequelae are reported. In persons suffering from respiratory failure, special consideration should be made on the treatment of complications, for example abdominal surgery. 7) Social measures, for example, residence with sheltered workshop and vocational training center are quite important to care the respiratory failure due to tuberculosis sequelae. Profile and follow up study of the residence and the training center are reported.(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of 2(3)-tert-butyl-4-hydroxyanisole pretreatment on cefpiramide binding to mouse glutathione S-transferases

Binding of cefpiramide (CPM) and other beta-lactam antimicrobial agents to 2(3)-tert-butyl-4-hydroxyanisole (BHA)-induced liver glutathione (GSH) S-transferases (EC 2.5.1.18) from CD-1 mice was studied. A marked induction of hepatic GSH S-transferase from mice fed BHA was observed. Gel chromatography of liver cytosol from mice fed BHA showed an increased binding of CPM, cefotetan and cefazolin to BHA-induced GSH S-transferases. The extent of their binding to GSH S-transferase seemed to be correlated with the extent of their excretion into the bile. Binding of CPM to the GSH S-transferase fraction was inhibited by both indocyanine green, which is known to bind liver GSH S-transferases intensively, and by cefoperazon, which is mainly excreted into the bile. This study suggests that GSH S-transferases are the main binding proteins of CPM in the liver cytosol fraction and play an important role as carrier proteins of CPM and some antimicrobial agents in mouse liver.

Agonist and antagonist binding of muscarinic acetylcholine receptors purified from porcine brain: interconversion of high- and low-affinity sites by sulfhydryl reagents

The affinity for muscarinic ligands of a preparation of muscarinic acetylcholine receptors purified from porcine brain was examined by means of competitive binding of [3H]quinuclidinylbenzylate and unlabeled ligands, followed by computer-assisted nonlinear regression analysis. The displacements by antagonists fitted a single-site model. In contrast, the displacements by agonists did not fit the single-site model and could be explained by assuming two populations of binding sites. The proportion of the sites with high affinity for muscarinic agonists (H-sites) ranged from 25 to 35% of the total number of sites. GTP had no effect on the displacements by agonists, a finding indicating that H-sites did not result from interaction between receptors and GTP-binding proteins. In the presence of dithiothreitol, the affinity for muscarinic ligands decreased. The largest effects were observed on the affinity for pirenzepine and that of H-sites for carbachol. Preincubation of the preparation with 5,5'-dithiobis(2-nitrobenzoic acid) resulted in an increase in the proportion of H-sites to 75% of the total number of binding sites. The results of sucrose density gradient centrifugation of the preparation indicated apparent heterogeneity as to molecular size of the receptors, but this heterogeneity did not correlate with that of the affinity for agonists. In addition, the receptors were detected as a single band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the preparation, regardless of the presence or absence of disulfide-reducing reagents. These results suggest that the redox state of thiol groups in the receptor molecules is relevant to their affinities for ligands.(ABSTRACT TRUNCATED AT 250 WORDS)

The interaction between D-2 dopamine receptors and GTP-binding proteins

D-2 dopamine receptors were solubilized from porcine striatal membranes with 0.3% sodium cholate/1 M NaCl and separated from the bulk of the guanine nucleotide-binding regulatory proteins (G-proteins) by Ultrogel AcA34 gel filtration chromatography. The partially purified D-2 receptors were reconstituted in phospholipid vesicles with Gi or Go purified from porcine brain. The dissociation constant (Kd) of the D-2 receptors in the reconstituted vesicles for [3H]spiperone binding was 82-89 pm, which was not affected by the presence or absence of G-proteins. The displacement curve for [3H]spiperone/dopamine was analyzed, assuming that there are two populations of binding sites. The Kd values for the binding sites with high affinity for agonists (HAS) and that for the binding sites with low affinity for agonists (LAS) were approximately 1 microM and 100 microM, respectively. The proportion of HAS was 8% when the receptor preparation was reconstituted into phospholipid vesicles without G-proteins, but it increased to 58-64% with increasing G-protein concentrations. The potency of Go was a little higher than that of Gi. The proportion of HAS in the presence of G-proteins decreased to about 11% on addition of GTP. When G-proteins were treated with islet-activating protein, GTP-sensitive HAS were not observed. These results indicate that at least 50% of the partially purified D-2 receptors interact with both Gi and Go.

[Laboratory and clinical studies of flomoxef]

Laboratory and clinical studies were performed on a new oxacephem antibiotic, flomoxef (FMOX, 6315-S). In vitro antibacterial activity of FMOX was evaluated in comparison to latamoxef (LMOX), cefmetazole (CMZ), cefazolin (CEZ) using clinically isolated strains of Gram-negative and Gram-positive bacteria. Antibacterial activities of FMOX were stronger than LMOX, CMZ, CEZ against Escherichia coli, Klebsiella but only slightly effective against Staphylococcus aureus. This antibiotic drug was administered to 5 patients consisting of 2 cases with pneumonia, one each with pyelonephritis, chronic bronchitis and urinary tract infection. The drug was given in 1 g drip infusion twice a day for 8 to 13 days. Clinical efficacies of FMOX were excellent in 1 case, good in 2, fair in 1, and unevaluable in 1. As for bacteriological effect of FMOX, organisms were eradicated in 3 cases. No side effect was noted and there was no abnormal change in laboratory findings.

Primary structure of porcine cardiac muscarinic acetylcholine receptor deduced from the cDNA sequence

The complete amino acid sequence of the porcine cardiac muscarinic acetylcholine receptor has been deduced by cloning and sequencing the cDNA. The tissue location of the RNA hybridizing with the cDNA suggests that this muscarinic receptor species represents the M2 subtype.

Dose-response curves of central and peripheral airways to nicotine injections in dogs

The dose-response curves of the central and peripheral airways to intravenously injected nicotine were studied in 55 anesthetized dogs. With intact vagi, nicotine caused a dose-dependent increase in central airway resistance (Rc) similar to the increase in peripheral airway resistance (Rp) at concentrations ranging from 4 to 64 micrograms/kg. However, the responses of both Rc and Rp fell progressively when sequential doses of nicotine greater than 256 micrograms/kg were administered. With intact vagi and the administration of propranolol, there was a greater increase in Rp than in Rc at a nicotine dose of 64 micrograms/kg (P less than 0.05). With vagotomy, the responsiveness of both central and peripheral airways to nicotine decreased with doses of nicotine less than 64 micrograms/kg, but with doses of nicotine greater than 256 micrograms/kg the suppressive effect of nicotine on both Rc and Rp was less than that seen with intact vagi. Under conditions in which the vagi were cut and atropine administered, the responsiveness of nicotine was even further depressed. Combinations either of atropine and chlorpheniramine or atropine and phenoxybenzamine also completely blocked reactions to nicotine. Additionally reactions to nicotine were completely blocked by hexamethonium. These results suggest that nicotine increases both Rc and Rp mainly through a vagal reflex and stimulation of the parasympathetic ganglia.

Cloning, sequencing and expression of complementary DNA encoding the muscarinic acetylcholine receptor

Cloning and sequence analysis of DNA complementary to porcine cerebral messenger RNA encoding the muscarinic acetylcholine receptor predict the complete amino-acid sequence of this protein. Expression of the complementary DNA produced functional muscarinic receptor in Xenopus oocytes. The muscarinic receptor is homologous with the beta-adrenergic receptor and rhodopsin in both amino-acid sequence and suggested transmembrane topography.

[The protocol of informing cancer patients of their condition]

The seven points we must consider in informing cancer patients of their condition are as follows: It is necessary that informing the patient has one or more of the following purposes: Patients have a right to know the truth. Any patient who desires to know the nature of his own disease has a right to be told. To avoid legal action. In cases where information is uncertain, which may cause difficulty for the patient. To avoid the burden of fabricating an untrue explanation. To help the patient bear radical treatment such as surgery, radiation and/or chemotherapy. To allow the patient to put an end to his/her life's work or finalize problems of property. To help the patient see the need to change his/her way of life. Are the conditions sufficient or not? Almost all these conditions must be clear. Is there any constructive purpose in informing the patient? Does the patient have a rational and receptive character? Is the patient in a mentally stable condition? Is these personal experience of death in the patient's family. Does the patient have a sure faith, thoughts and/or views of life and death? Is there enough cooperative work among the medical team? Is there enough cooperative work among the patient's family? Who tells the truth to the patient? Is there a need to inform the patient in stages? At what stage of the disease is the patient told? Where is the patient told? Comprehensive care must be given after informing the patient of his/her condition.

Reconstitution of the muscarinic acetylcholine receptor. Guanine nucleotide-sensitive high affinity binding of agonists to purified muscarinic receptors reconstituted with GTP-binding proteins (Gi and Go)

Muscarinic acetylcholine receptors purified from porcine brain were reconstituted with two kinds of GTP-binding proteins (Gi and Go). The binding of agonists was affected by guanine nucleotides when the receptor was reconstituted with either Gi or Go, but not in the absence of one of the GTP-binding proteins. The displacement curves with agonists for the [3H]quinuclidinyl benzylate [( 3H]QNB) binding were explained by assuming there are two sites with different affinities for a given agonist. The proportion of the high affinity site increased with increasing concentrations of the GTP-binding proteins, and the maximum value represented 50-70% of the total [3H]QNB-binding sites. Reconstitution of the receptor with both Gi and Go did not increase the proportion any further. These results indicate that Gi and Go interact with the same site, which rules out the possibility that there are two kinds of muscarinic receptors, one interacting with Gi and the other with Go. GDP as well as GTP decreased the affinity for the agonists of the muscarinic receptors reconstituted with Gi or Go. The conversion of GDP to GTP during the incubation was less than 1%, indicating that the effect of GDP is not due to its conversion to GTP, and that the binding of either GTP or GDP with the GTP-binding proteins suppresses their interaction with the receptor.

Functional interaction of purified muscarinic receptors with purified inhibitory guanine nucleotide regulatory proteins reconstituted in phospholipid vesicles

The GTP binding regulatory protein (Ni involved in adenylate cyclase inhibition was purified from rat brain and reconstituted, together with muscarinic cholinergic receptors purified from porcine brain, into phospholipid vesicles. Guanosine 5'-O-(3-[35S]thio)-triphosphate ([35S]GTP gamma S) binding and GTP hydrolyzing activities of reconstituted Ni were stimulated by the addition of a muscarinic agonist, carbachol. The effect of carbachol was to increase the Vmax values of these activities, but the Km values were also increased slightly in most cases. Carbachol bound to vesicles with the same order of magnitude of Km as that for stimulation of GTPase. The affinity of this binding was reduced by GTP gamma S, indicating that the high-affinity receptor-Ni complex was formed in a GTP-dependent manner in reconstituted vesicles. Incubation of Ni with NAD and islet-activating protein (IAP), pertussis toxin, caused ADP-ribosylation of the alpha-subunit of Ni. The criteria for the receptor-Ni interaction, i.e. carbachol stimulation of the activities of Ni and the GTP gamma S effect on carbachol binding, were no longer observed, when this IAP-treated Ni, instead of the nontreated Ni, was reconstituted into vesicles, though there was no difference between IAP-treated and nontreated Ni in their basal activities observable without carbachol. No, the protein with a character very similar to Ni in rat brain, was also coupled to muscarinic receptors when they were reconstituted into vesicles under the same conditions. Thus, GTP-binding proteins serving as the substrate of IAP-catalyzed ADP-ribosylation are capable of interaction functionally with muscarinic receptors in phospholipid vesicles.

Primary structure of the alpha-subunit of bovine adenylate cyclase-inhibiting G-protein deduced from the cDNA sequence

The primary structure of the alpha-subunit of the adenylate cyclase-inhibiting G-protein (Gi) has been deduced from the nucleotide sequence of cloned DNA complementary to the bovine cerebral mRNA encoding the polypeptide. A much higher degree of amino acid sequence homology is observed between the alpha-subunits of Gi and transducin (68%) than between those of Gi and the adenylate cyclase-stimulating G-protein (Gs) (43%) or between those of transducin and Gs (42%).

Chronic treatment with nifedipine does not change the number of [3H]nitrendipine and [3H]dihydroalprenolol binding sites

Possible receptor changes occurring after withdrawal of chronic nifedipine treatment or chronic propranolol treatment were examined by administering nifedipine (100 mg/kg per day) or propranolol (45 mg/kg per day) to rats for 2 weeks and then withdrawing treatment [3H]Nitrendipine and [3H]DHA binding were measured in membrane fragments of the ventricle. In propranolol-treated rats, 8 h after the last administration, the maximum binding for [3H]DHA was significantly increased from 79.9 +/- 8.0 to 139.8 +/- 12.8 fmol/mg protein (mean +/- S.E.); the dissociation constant was significantly increased from 4.9 +/- 0.7 to 10.7 +/- 1.2 nM. On the other hand, in nifedipine-treated rats, 12 and 48 h after the last administration, [3H]nitrendipine binding and [3H]DHA binding had not changed significantly. These results indicate that the mechanism of the calcium antagonist withdrawal syndrome may be different from that of beta-blocker withdrawal syndrome.

Functional reconstitution of purified muscarinic receptors and inhibitory guanine nucleotide regulatory protein

Muscarinic receptors trigger several different responses including an increase in concentration of cyclic GMP, a decrease in cyclic AMP concentration, breakdown of polyphosphoinositides and changes in ion permeability. It is not yet clear whether these reactions occur sequentially or independently and which directly coupled to the muscarinic receptor. Several lines of evidence indicate that muscarinic receptors in many, if not all, cell types are coupled to the inhibitory guanine nucleotide regulatory protein (Ni or Gi) of adenylate cyclase. To provide direct evidence for this coupling, we have reconstituted muscarinic receptors purified from porcine brain with Ni purified from rat brain in a phospholipid vesicle. Here, we report that the GTPase activity of Ni is stimulated by carbachol. This action is blocked by the simultaneous addition of atropine and is not observed when the Ni protein is ADP-ribosylated. We conclude that one function of the muscarinic receptor is the activation of Ni.

Purification of the muscarinic acetylcholine receptor from porcine brain

The muscarinic acetylcholine receptor of porcine cerebrum has been purified to apparent homogeneity by affinity chromatography, with conjugated 3-(2'-aminobenzhydryloxy)tropane (ABT) as described previously (Haga, K., and Haga, T. (1983) J. Biol. Chem. 258, 13575-13579). In a single step purification using 900 ml of digitonin/cholate-solubilized preparations and 300 ml of the ABT-agarose gel, we obtained, in a yield of 10-15%, more than 250 pmol of muscarinic receptors which bind [3H]N-methylscopolamine with a specific activity of 1,000-5,000 pmol/mg of protein (1,000-5,000-fold purification). The muscarinic receptors eluted from the ABT-agarose gel with 0.1 mM atropine were adsorbed to hydroxylapatite and then recovered as a concentrated solution. Muscarinic receptors were further purified by rechromatography with the same gel or by gel permeation high pressure liquid chromatography. The amino acid composition of the purified receptor was determined, and the specific activity of the purified preparation was estimated to be 13,100 pmol/mg of protein on the basis of amino acid composition. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified receptors with or without radioiodination revealed a single, major band with an apparent Mr of 70,000 either by silver staining or radioautogram. The major band corresponded to the band which specifically bound [3H]propylbenzylcholine mustard (irreversible muscarinic ligand). The purified receptor showed essentially the same specificity for muscarinic ligands as unpurified receptors.

Primary structure of the alpha-subunit of transducin and its relationship to ras proteins

A group of membrane-associated guanine nucleotide binding proteins (G-proteins) are essential for transducing signals generated at cell-surface receptors into changes in cellular function and metabolism. These proteins are a complex of three subunits designated alpha, beta and gamma. The alpha-subunit is responsible for binding guanine nucleotides and seems to be characteristic of each protein. Transducin, a member of this protein family, mediates visual transduction by coupling the signal of photolysed rhodopsin with activation of a cyclic GMP phosphodiesterase. We have now cloned and sequenced the complementary DNA encoding the alpha-subunit of bovine retinal transducin and from this we have deduced the complete amino-acid sequence. The transducin alpha-subunit shares several homologous amino-acid sequences with ras gene products. The homologous segments correspond mostly to the regions thought to be involved in the guanine nucleotide binding and GTPase activity of ras proteins and to the ADP-ribosylation sites of the transducin alpha-subunit.