Hindquarter sympathetic tone induced by small blood loss in conscious rats

We have designated the hindquarter (or terminal aortic) vascular resistance (HQR) of the rat as hindquarter compensator (HC) because it increases after such hypotensive interventions as pentobarbital anesthesia and nitrate administration, presumably due to reflex excitation of regional vasoconstrictor fibers. The aim of the present study was to observe whether the HC mechanism is also mobilized in response to hemorrhage. Rats were implanted with a 1.5 or 2 mm diameter electromagnetic flow probe at the terminal aorta for measurement of hindquarter flow (HQF). An indwelling catheter was placed in the right common carotid artery to measure arterial pressure (AP) and withdraw blood. Experiments were performed in conscious rats two or three days after implantation. HQR was calculated by dividing AP by HQF. About 10 min after withdrawing blood (0.3 ml/100 g body weight), ganglionic blockade with hexamethonium bromide significantly decreased HQR, which indicated a mobilization of the HC mechanism, a change not observed with superior mesenteric resistance. A quantitatively similar change was observed in HQR after withdrawing double the amount of blood, i.e., 0.6 ml/100 g body weight, suggesting that the HC mechanism is activated almost fully by the relatively small amount of blood loss of 0.3 ml/100 g body weight.

Low-affinity nerve growth factor receptor is associated with motoneuron axonal pathways

The unidentified cell-surface antigen recognized by monoclonal antibody M7412 is distributed along motoneuron axonal outgrowth pathways in chicken embryos. To better characterize its role in motoneuron development, the M7412 antigen was purified from chicken embryos by immunoaffinity chromatography. Its N-terminal amino acid sequence corresponded to that predicted for chicken low-affinity nerve growth factor receptor (LNGFR). Experiments were performed to confirm that LNGFR was indeed the antigen recognized by M7412. First, M7412 bound to recombinant chicken LNGFR expressed in mammalian cells. Second, a rabbit serum raised to the purified antigen showed the same staining pattern in chicken embryos as did M7412. Lastly, a novel method for direct detection of nerve growth factor (NGF) bound to its receptors was used to show that in mixed spinal cord cultures, only neurons that expressed M7412 antigen had low-affinity binding sites for NGF. Furthermore, at the subcellular level, M7412 labeling was co-localized with bound NGF. The M7412 antigen is thus chicken LNGFR, whose role in motoneuron outgrowth pathways is discussed.

A novel heterologous gene expression system in Saccharomyces cerevisiae using the isocitrate lyase gene promoter from Candida tropicalis

We have found that the upstream region of the isocitrate lyase gene (UPR-ICL) from the n-alkane-utilizing yeast Candida tropicalis was functional in Saccharomyces cerevisiae as a novel promoter with nonfermentable carbon sources, such as oleic acid, acetate, ethanol, and glycerol/lactate. The expression of two foreign genes coding for beta-galactosidase from Escherichia coli (LacZ) and glutamate decarboxylase from rat brain was carried out under the control of UPR-ICL. Expression of LacZ was repressed by glucose and enhanced over 300-fold by acetate. When an expression vector pWI3 containing multicloning sites between UPR-ICL and the transcriptional terminator of the isocitrate lyase gene (TERM-ICL) was used, the smaller isoform of glutamate decarboxylase (GAD65) was highly produced in a soluble and active form. These results demonstrate that the novel expression system using UPR-ICL and TERM-ICL from C. tropicalis is useful for the production of heterologous proteins in S. cerevisiae.

Increased spontaneous production of IL-8 in peripheral blood monocytes from the psoriatic patient: relation to focal infection and response to treatments

To evaluate the contribution of peripheral blood monocytes (PBMC) to epidermotropic inflammatory reactions in psoriasis, using an enzyme-linked immunosorbent assay we measured spontaneous interleukin-8 (IL-8) production in PBMC obtained from patients with psoriasis. IL-8 production in the psoriatic PBMC was significantly higher than that in normal control PBMC. Plasma IL-8 levels in psoriatic patients were also moderately increased compared to normal control levels. IL-8 production in PBMC was closely related to the clinical severity of psoriasis and to the response to treatment, including systemic methotrexate (MTX) treatment and tonsillectomy. IL-8 production in PBMC was also positively related to the production of interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) in these cells. We speculate that the chemotactic cytokine IL-8 contributes to the development of psoriatic skin lesions, and mediates inflammatory reactions from the inflammatory focus to the psoriatic lesions.

A novel promoter, derived from the isocitrate lyase gene of Candida tropicalis, inducible with acetate in Saccharomyces cerevisiae

When the isocitrate lyase gene, containing 5'-upstream and 3'-flanking regions, of an n-alkane-assimilating yeast Candida tropicalis was introduced into Saccharomyces cerevisiae, the enzyme was functionally overexpressed in the cells grown on acetate. The amount of the recombinant isocitrate lyase expressed in S. cerevisiae was as much as 30% of the total soluble proteins in the cells, being comparable to that with GAL7 functional under the control of galactose. The expression was also observed when the cells were grown on glycerol, lactate, ethanol or oleate. These facts indicate that the isocitrate lyase gene upstream region (UPR-ICL) contains a strong promoter functional in S. cerevisiae. UPR-ICL is active as a promoter on cheap carbon sources such as acetate and nonconventional carbon sources such as oleate, whereas many conventional strong promoters demand relatively expensive sugars or sugar derivatives. Therefore, it is promising to construct an economical recombinant protein production system by using UPR-ICL.

The upstream region of the isocitrate lyase gene (UPR-ICL) of Candida tropicalis induces gene expression in both Saccharomyces cerevisiae and Escherichia coli by acetate via two distinct promoters

The upstream region of the isocitrate lyase gene (UPR-ICL, 1530bp) of an n-alkane-utilizable yeast, Candida tropicalis, induced gene expression in another yeast, Saccharomyces cerevisiae, when the yeasts were grown on acetate. Surprisingly, UPR-ICL displayed the same regulatory function in the bacterium Escherichia coli when grown on acetate. We determined the interesting nucleotide sequence of UPR-ICL. The deletion analysis of UPR-ICL in both cells revealed the presence of two distinct promoters: one was localized at -394 to -379 and regulated gene expression in S. cerevisiae; the other was located near the initiation codon and regulated gene expression in E. coli. The two promoter sequences were similar, but not identical to regulatory elements that have been previously reported in S. cerevisiae and E. coli, respectively. Accordingly, the possibility of novel regulatory mechanisms could not be excluded. This is an interesting example of the presence of distinct cis-acting regulatory elements responsible for the induction of gene expression in one gene by acetate in both S. cerevisiae and E. coli. Preservation of such promoters through evolution is also discussed.

[Experimental studies on the influence of duodenal contents on the mucosa of gastric remnant]

Using the PCNA staining method, we examined the histopathological changes and cytokinetics on the gastric mucosa of the gastric remnant at the anastomosis 10, 20 and 50 weeks after gastrectomy. We conducted the distal gastrectomy in rats and divided them into three groups: Group 1, in which "a sham" operation was performed; Group 2, in which reflux of duodenum fluids was prevented by Roux-en Y anastomosis; and Group 3, in which reflux of duodenum fluids was allowed by gastro-jejunal anastomosis. Adenocarcinoma developed only at the anastomosis of the afferent loops in animals of Group 3 directly exposed to duodenum fluid. The PCNA labeling index at the anastomosis of the afferent loop was high from the early stages. In addition, labeling index tended to increase gradually, and PCNA positive cells were diffusely scattered, which indicated acceleration of cytosis. From these results, we concluded that the reflux of duodenum fluid was essential for the development of cancer in the remnant stomach. Moreover, cytosis was closely related to the development of epithelial cancer of the gastric mucosa at the anastomosis of the remnant stomach.

[A ornithine decarboxylase activity and proliferating cell nuclear antigen in gastric cancer]

To investigate ornithine decarboxylase (ODC) activity and proliferating cell nuclear antigen (PCNA) in gastric cancer, ODC activity and PCNA were measured in 50 resected samples. The relationship between both and clinicopathologic factors was examined. ODC activity was 473.3 +/- 54.7 pmol CO2/60 min/mg protein in tumors, and 273.5 +/- 38.3 pmol CO2/60 min/mg protein in normal mucosa. ODC activity in tumors was significantly higher than that of normal mucosa. ODC activity in tumors was significantly high in gross type 4, maximum diameter more than 10 cm, depth se, infiltrative growth (INF) gamma, positive lymph vessel invasion and positive lymph node metastasis. PCNA-LI was 24.7 +/- 1.5% in tumors, and 13.9 +/- 1.1% in normal mucosa. PCNA-LI of tumors was significantly higher than that of normal mucosa. PCNA-LI of tumors was significantly high in gross type 2, histological type tub 2 and por, depth ss beta and se, IFN beta, positive lymph vessel invasion, positive venous invasion, and positive lymph node metastasis. ODC activity and PCNA-LI were closely related in normal mucosa, showing a correlation coefficient of 0.730. On the other hand, their relationship was weak in tumors, showing a correlation coefficient of 0.417. These results suggest the differentiation of value between ODC activity and PCNA-LI in gastric cancer. In gastric cancer, ODC activity and PCNA-LI in tumors may be good markers of lymph node metastasis. Furthermore, PCNA-LI may be a good marker of hematogenous metastasis.

Hindquarter vascular resistance as compensator for hypotension in conscious rats

The purpose of this study was to test whether hindquarter (terminal aortic) vascular resistance uniquely increases in order to compensate for interventions which result in a lowering of arterial pressure. Changes in hindquarter resistance were compared to changes in superior mesenteric resistance after the administration of the nitrovasodilator drug, molsidomine. Hindquarter blood flow or superior mesenteric flow was measured in conscious rats using an electromagnetic flow probe implanted around the terminal aorta or the superior mesenteric artery, respectively. Twenty minutes after an intravenous bolus injection of molsidomine (1 mg/kg), ganglionic blockade with hexamethonium bromide (25 mg/kg, i.v.) significantly decreased hindquarter resistance, but not superior mesenteric resistance. In the absence of molsidomine, ganglionic blockade has no effect on resistance in either vascular bed. These findings suggest that excitation of sympathetic vasoconstrictor fibers supplying the hindquarters but not those supplying the superior mesenteric area occurred in response to the hypotensive effect of molsidomine. This is consistent with the hypothesis that augmenting-hindquarter resistance is the first line of defense against hypotensive interventions.

Release of sympathetic neurotransmitter evoked by electrical stimulation is increased in the chronically decentralized artery

The present study was performed to confirm our previous proposal that the increase in neurotransmitter release is responsible for the supersensitivity of chronically decentralized artery to transmural nerve stimulation (TNS) in the rabbit. The ear artery was decentralized unilaterally by removing the preganglionic fiber proximal to the superior cervical ganglion (SCG), and the ear arteries and SCG were dissected 8 weeks after the operation. The increase in the tritium overflow induced by TNS from the chronically decentralized artery, which had been incubated with 3H-noradrenaline (NA) for 1 hr, was markedly increased at lower frequencies (0.1 and 0.2 Hz) than that from the control artery, whereas there was no difference at higher frequencies (> 0.5 Hz). No difference was observed in the neuronal uptake of 3H-NA during incubation for 1 hr between the control and decentralized arteries. There was also no change in the contents of catecholamines in both the artery and SCG after chronic decentralization, when assayed by a radioenzymatic procedure. In conclusion, the results obtained indicate that the supersensitivity to TNS after chronic decentralization is not due to the deranged catecholamine uptake and storage mechanisms in adrenergic nerve terminals and augmented transmitter biosynthesis, but due to the increased release of transmitter in response to low frequencies of TNS.

Vasoconstricting effect of vasopressin on regional vascular beds in conscious rats after ganglionic blockade

We analyzed the vasoconstrictor effects of arginine vasopressin (AVP) on regional arteries before and after ganglionic blockade with hexamethonium. Simultaneous measurements of mean arterial pressure and regional flows were obtained in conscious rats, using chronically implanted electromagnetic flow probes. Regional vascular resistance was calculated as mean arterial pressure divided by regional flow. AVP was applied intravenously as a bolus, at doses ranging from 5 x 10(-11) to 5 x 10(-8) g/kg. AVP increased mean arterial pressure, decreased superior mesenteric, renal and terminal aortic flows (supplied mainly for the hindquarter vascular area), and increased superior mesenteric, renal and terminal aortic (hindquarter) resistances in a dose-dependent manner. Ganglionic blockade decreased mean arterial pressure and renal resistance significantly, whereas there were no significant differences between changes in resistance before and after ganglionic blockade in superior mesenteric or terminal aortic areas. This suggested the presence of basal sympathetic vasoconstrictor tone in the renal area. After ganglionic blockade, the pressor effect of AVP was enhanced significantly. The increase in renal resistance induced by AVP was augmented after ganglionic blockade, whereas increases in superior mesenteric or terminal aortic resistance remained unchanged following ganglionic blockade. Our data suggest that the vasoconstrictor effect of AVP on renal vascular area is reduced by a mechanism which inhibits renal sympathetic basal tone.

Peroxisomal acetoacetyl-CoA thiolase of an n-alkane-utilizing yeast, Candida tropicalis

Two genes encoding acetoacetyl-CoA thiolase (thiolase I; EC 2.3.1.9), whose localization in peroxisomes was first found with an n-alkane-utilizing yeast, Candida tropicalis, were isolated from the lambda EMBL3 genomic DNA library prepared from the yeast genomic DNA. Nucleotide sequence analysis revealed that both genes contained open reading frames of 1209 bp corresponding to 403 amino acid residues with methionine at the N-terminus, which were named as thiolase IA and thiolase IB. The calculated molecular masses were 41,898 Da for thiolase IA and 41,930 Da for thiolase IB. These values were in good agreement with the subunit mass of the enzyme purified from yeast peroxisomes (41 kDa). There was an extremely high similarity between these two genes (96% of nucleotides in the coding regions and 98% of amino acids deduced). From the amino acid sequence analysis of the purified peroxisomal enzyme, it was shown that thiolase IA and thiolase IB were expressed in peroxisomes at an almost equal level. Both showed similarity to other thiolases, especially to Saccharomyces uvarum cytosolic acetoacetyl-CoA thiolase (65% amino acids of thiolase IA and 64% of thiolase IB were identical with this thiolase). Considering the evolution of thiolases, the C. tropicalis thiolases and S. uvarum cytosolic acetoacetyl-CoA thiolase are supposed to have a common origin. It was noticeable that the carboxyl-terminal regions of thiolases IA and IB contained a putative peroxisomal targeting signal, -Ala-Lys-Leu-COOH, unlike those of other thiolases reported hitherto.

Crystallographic characterization of a PHO4-DNA complex

Crystals have been obtained of the DNA-binding domain of the yeast transcription factor PHO4 in complexes with several synthetic fragments of DNA with appropriate cognate sequences. Crystals suitable for X-ray diffraction studies were produced in the case of a complex of the protein with a 17 base-pair fragment of DNA from a solution in polyethylene glycol and calcium chloride. The crystals have the space group of P4(1)2(1)2 or P4(3)2(1)2 with unit cell dimensions a = b = 56.7 A, c = 447.8 A. The diffraction data at 3 A resolution were collected using synchrotron radiation with a Weissenberg camera for macromolecular crystallography.

Effects of alkyl alcohols and related chemicals on rat liver structure and function. III. Physiochemical properties of ethanol-, propanol- and butanol- treated rat liver mitochondrial membranes

The physicochemical properties of mitochondria in liver tissue obtained from rats given 32% ethanol, 32% propanol or 6.9% butanol in drinking water for up to 3 months were investigated using differential scanning calorimetry and fluorescence polarization measurements. The results obtained were as follows: 1) Phospholipids extracted from mitochondria showed increases in the relative amounts of phosphatidylcholine, phosphatidylinositol and phosphatidylserine, and a decrease in the relative amount of phosphatidylethanolamine. An increase in the unsaturated/saturated fatty acid ratio of phospholipids was also observed. 2) Elevation of the thermotropic lipid phase transition temperature with a decrease in the enthalpy value (delta H) was revealed by differential scanning calorimetry. 3) The elevation of the lipid phase transition temperature was detected also by fluorescence polarization measurements using 1,6-diphenyl-1,3,5-hexatriene (DPH) as a probe. Elevation of mitochondrial membrane fluidity was found in some of the experimental animals, but most showed no changes in comparison with the control. A possible role of membrane fusion in the mechanism of formation of ethanol-, propanol- and butanol-induced hepatic megamitochondria is discussed on the basis of these results.

Sympathetic Vasoconstrictor Tone Induced by Pentobarbital Anesthesia in Hindquarters of Rats

Hindquarter (terminal aortic) blood flow (HQF) and arterial pressure (AP) were observed in rats with an electromagnetic flow probe implanted around the terminal aorta and an arterial indwelling cannula. Hindquarter peripheral resistance (HQR) was calculated by dividing mean AP by HQF. Under pentobarbital anesthesia, HQR was decreased significantly (p less than 0.001) by ganglionic blockade with hexamethonium bromide (C6). Since C6 does not change HQR significantly without anesthesia, we interpret that pentobarbital anesthesia generated a sympathetic vasoconstrictor tone in hindquarter resistance vessels. This was further substantiated by the observation that the increase in HQR on infusion of vasopressin was obscure under pentobarbital anesthesia: Presumably, the increase was offset by reflex inhibition of the hindquarter tone induced by anesthesia. The generation of hindquarter vasoconstrictor tone by pentobarbital was for the most part ascribable to the baroreceptor reflex to compensate for the depressor effect of this anesthetic, because it was greatly diminished after severance of the buffer nerves.

Presence of two transcribed malate synthase genes in an n-alkane-utilizing yeast, Candida tropicalis

The presence of two genomic DNA regions encoding malate synthase (MS) was shown by Southern blot analysis of the genomic DNA from an n-alkane-assimilating yeast, Candida tropicalis, using a partial MS cDNA probe, in accordance with the fact that two types of partial MS cDNAs have previously been isolated. This was also confirmed by the restriction mapping of the two genes screened from the yeast lambda EMBL library. Nucleotide sequence analysis of the respective genomic DNAs, named MS-1 gene and MS-2 gene, revealed that both regions encoding MS had the same length of 1,653 base pairs, corresponding to 551 amino acids (molecular mass of MS-1, 62,448 Da; MS-2, 62,421 Da). Although 29 nucleotide pairs differed in the sequences of the coding regions, the number of amino acid replacements was only one: 159Asn (MS-1)----159Ser (MS-2). In the 5'-flanking regions, there were replacements of four nucleotide pairs, deletion of one pair, and insertion of four pairs. In spite of the fact that two genomic genes were present and transcribed, RNA blot analysis demonstrated that only one band (about 2 kb) was observable even when the carbon sources in the cultivation medium were changed. A comparison of the amino acid sequences was made with MSs of rape (Brassica napus L.), cucumber seed, pumpkin seed, Escherichia coli, and Hansenula polymorpha. A high homology was observed among these enzymes, the results indicating that the protein structure was relatively well conserved through the evolution of the molecule.(ABSTRACT TRUNCATED AT 250 WORDS)

High level expression of isocitrate lyase gene of n-alkane-utilizing yeast Candida tropicalis in Saccharomyces cerevisiae

The genomic DNA of peroxisomal isocitrate lyase (ICL) isolated from an n-alkane-assimilating yeast, Candida tropicalis, was truncated to utilize the original open reading frame under the control of the GAL7 promoter and was expressed in Saccharomyces cerevisiae. The recombinant ICL was synthesized as a functionally active enzyme with a specific activity similar to the enzyme purified from C. tropicalis, and was accounted for approximately 30% of the total extractable proteins in the yeast cells. This recombinant enzyme was easily purified to homogeneity. N-Terminal amino acid sequence, molecular masses of native form and subunit, amino acid composition, peptide maps, and kinetic parameters of the recombinant ICL were essentially the same as those of ICL purified from C. tropicalis. From these facts, S. cerevisiae was suggested to be an excellent micro-organism to highly express the genes encoding peroxisomal proteins of C. tropicalis.

Characterization of a new human apolipoprotein A-I Yame by direct sequencing of polymerase chain reaction-amplified DNA

A new genetic variant apolipoprotein (apo), A-I Yame, was discovered during screening for apoA-I genetic variants with isoelectric focusing gel electrophoresis. To investigate the structural abnormality of apoA-I Yame, we amplified the apoA-I gene isolated from the proband's peripheral blood leukocytes with the polymerase chain reaction (PCR) method and directly sequenced these PCR fragments. ApoA-I Yame was found to have aspartic acid (GAC) substituted by tyrosine (TAC) at residue 13. We also identified this substitution by an automated DNA sequencer. This substitution was confirmed with amino acid sequencing of the isolated apoA-I Yame by Immobiline gel electrophoresis. This combined method, direct PCR from genomic DNA-derived individual peripheral blood leukocytes and subsequent direct sequencing, can be used to identify the entire sequence of apoA-I in a short period of time. Furthermore, with this method, it is possible to identify both alleles in heterozygous individuals.

[Reevaluation of the unilateral pulmonary artery occlusion test--hemodynamics after lobectomy and pneumonectomy for lung cancer]

After lobectomy, it is recognized that functional as well as absolute reduction occurs in residual lobes of the operated side. So whether lobectomy is indicated or not is determined by the same criteria as those for pneumonectomy, namely, by the unilateral pulmonary artery occlusion (UPAO) test. However, is it really appropriate to use the same criteria for both lobectomy and pneumonectomy? To answer to this question, in patients with lung cancer we compared the hemodynamics after lobectomy (13 cases) and pneumonectomy (14 cases) with that at the UPAO test. After pneumonectomy, the mean pulmonary arterial wedge pressure (mPWP) was significantly lower than that on the preoperative day and at the test. It seemed that hypovolemic change occurred in the hemodynamics after pneumonectomy. After pneumonectomy, the pulmonary arteriolar resistance index (PARI) was significantly higher than the preoperative value. It was the same as that as at the time of the UPAO test. The total pulmonary vascular resistance index (TPVRI) at the time of the test was significantly higher than the preoperative value, but the TPVRI after pneumonectomy was not significantly higher. The TPVRI tended to decrease after pneumonectomy, compared to the value predicated by the test. These results indicated that some of the cases judged inoperable on the basis of the UPAO test might be operable. On the day of lobectomy, the PARI was significantly higher than the preoperative value, but significantly lower than that at the time of the test. The cardiac index (CI) was significantly higher and the mPWP was significantly lower than each preoperative value.(ABSTRACT TRUNCATED AT 250 WORDS)

Similarity of expression of low molecular weight G proteins smg p21A and ras p21 in normal and malignant human tissues

We prepared monoclonal antibodies specific for smg p21A, one of the low molecular weight GTP-binding proteins and possibly a suppressor molecule for ras p21. Two monoclonal antibodies (T22 and T212) reacted with smg p21A but not with Ki-ras p21, both of which were produced by Escherichia coli. These two clones detected an Mr 21,000 band in one-dimensional immunoblotting of extracts of a human pancreatic cancer cell line which was indistinguishable from a band detected by RASK-3, a monoclonal antibody specific for ras p21. However, T22 and T212 detected a single spot in two-dimensional immunoblotting that was clearly different from the three spots detected in the same cellular extracts by RASK-3. A series of normal and malignant human tissues were examined for the expression of smg p21A and ras p21 by immunohistochemical methods utilizing T22 and RASK-3. In essentially all tissues examined, both normal and malignant, smg p21A and ras p21 were expressed with great similarity. Expression of both molecules in all malignant tissues examined was coincident with that in normal tissues except that gastric cancer showed increased expression of the two molecules in comparison with normal gastric tissue.

High-level secretion of human apolipoprotein E produced in Escherichia coli: use of a secretion plasmid containing tandemly polymerized ompF-hybrid gene

A gene encoding the mature form of human apolipoprotein E (h-apoE) was fused to the secretion signal coding sequence of the Escherichia coli major outer membrane protein F (ompF) which was preceded by a consensus Shine-Dalgarno sequence. Two copies of this hybrid gene were inserted tandemly into an expression vector and expressed in E. coli under the transcriptional control of two tac promoters regulated by lac repressors. By the addition of isopropyl-beta-D-thiogalactopyranoside (IPTG) to the growth media, cells synthesized h-apoE at the level of 27.2 micrograms per A600 and up to 22% of the total cellular protein. The h-apoE produced by E. coli was processed precisely, secreted into the periplasmic space and formed protein aggregates there. However, despite aggregation, they were easily dissolved in water and actively formed protein-lipid complexes with dimyristoyl phosphatidyl choline (DMPC). These results demonstrated that E. coli cells are able to synthesize and secrete a large amount of active h-apoE using a prokaryotic signal sequence.

Differential expression of the N-myc, c-fos, and smg p25A genes in human neuroblastoma cells during neuronal and Schwannian differentiation

We have examined expression of the N-myc, c-fos and smg p25A genes in two human neuroblastoma cell lines during their differentiation. The decrease in the N-myc gene expression and the increase in the c-fos gene expression are observed during the differentiation of NB-1 cells into neuronal cells and of GOTO cells into Schwann-type cells. On the other hand, the smg p25A, a ras p21-like small GTP-binding protein, gene expression is increased in NB-1 cells but not in GOTO cells during their differentiation, suggesting that smg p25A is closely associated with the neuronal phenotype of neuroblastoma cells.

Molecular cloning and characterization of a novel type of regulatory protein (GDI) for smg p25A, a ras p21-like GTP-binding protein

We recently purified to near homogeneity a novel type of regulatory protein for smg p25A, a ras p21-like GTP-binding protein, from bovine brain cytosol. This regulatory protein, named smg p25A GDP dissociation inhibitor (GDI), regulates the GDP-GTP exchange reaction of smg p25A by inhibiting dissociation of GDP from and subsequent binding of GTP to it. In the present studies, we isolated and sequenced the cDNA of smg p25A GDI from a bovine brain cDNA library by using an oligonucleotide probe designed from the partial amino acid sequence of purified smg p25A GDI. The cDNA has an open reading frame that encodes a protein of 447 amino acids with a calculated Mr of 50,565. This Mr is similar to those of the purified smg p25A GDI estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and sucrose density gradient ultracentrifugation, which are about 54,000 and 65,000, respectively. The isolated cDNA is expressed in Escherichia coli, and the encoded protein exhibits GDI activity. smg p25A GDI is hydrophilic overall, except for one hydrophobic region near the N terminus. smg p25A GDI shares low amino acid sequence homology with the Saccharomyces cerevisiae CDC25-encoded protein, which has been suggested to serve as a factor that regulates the GDP-GTP exchange reaction of the yeast RAS2-encoded protein, but not with the beta gamma subunits of GTP-binding proteins having an alpha beta gamma subunit structure, such as Gs and Gi. The smg p25A GDI mRNA was present in various tissues, including not only tissues in which smg p25A was detectable but also tissues in which it was not detectable. This fact has raised the possibility that smg p25A GDI interacts with another G protein in tissues in which smg p25A is absent.

[A study of ultrasonic scaling in combination with povidone-iodine solution. (1)]

The effects of ultrasonic scaling in combination with povidone-iodine solution were examined clinically. The results obtained were as follows: 1. Three days after instrumentation, significant improvement was found in all experimental groups. Thereafter the improvement was at the same level and backing in each group. 2. Clinical findings, with exception of plaque index, showed improvement with ultrasonic scaling in combination with povidone-iodine solution in comparison with ultrasonic scaling alone and root planing.