Induction of mutation of a synthetic c-Ha-ras gene containing hypoxanthine

The second base of codon 61 of a synthetic c-Ha-ras gene was replaced with a hypoxanthine residue in a site-specific manner. Transfection of this gene into NIH3T3 cells by the calcium phosphate procedure resulted in increased focus formation. Total DNA was extracted from transformed cells, and the sequences of the inserted c-Ha-ras DNA were analyzed by the polymerase chain reaction-single-strand conformation polymorphism method. Mutations with A (or hypoxanthine) to G transition were detected exclusively. These results suggest that the synthetic c-Ha-ras gene can be used for investigations of mutagenesis caused by DNA lesions.

Lack of effect of islet amyloid polypeptide on hepatic glucose output in the in situ-perfused rat liver

Islet amyloid polypeptide (IAPP), a novel peptide isolated from islet amyloid deposits in patients with insulinoma and non-insulin-dependent diabetes mellitus (NIDDM), has been reported to be cosecreted with insulin from pancreatic beta cells and to inhibit glucose uptake and glycogen synthesis in muscle tissue in vitro. We investigated the effects of the synthesized, rat-amidated form of IAPP on hepatic glucose output, and IAPP extraction, using an in situ flow-through perfusion system in rats to elucidate the actions of IAPP on the liver. The IAPP (10(-8) mol/L) alone had no effects on the hepatic glucose release. Infusion of 6 x 10(-11) mol/L glucagon alone resulted in an expected elevation in glucose production (30.0 +/- 1.7 mumol/35 min/g liver). Insulin (3 x 10(-10) mol/L) submaximally decreased the glucagon-stimulated glucose production to 73% (from 30.0 +/- 1.7 to 22.0 +/- 1.4 mumol/35 min/g liver; n = 7, P less than .01). A simultaneous infusion of 10(-8) mol/L IAPP did not influence the glucagon-stimulated glucose production (27.6 +/- 1.2 mumol/35 min/g liver) or the insulin-dependent inhibition of glucagon-stimulated glucose production (22.6 +/- 1.3 mumol/35 min/g liver). IAPP extraction by the liver in a single passage was minimal, in contrast to approximately 50% hepatic insulin extraction. These results indicate that IAPP does not play any important role in modulating glycogen metabolism in the liver.

Giant basal prolactinoma extending into the nasal cavity

An unusual case of a giant prolactinoma extending to the nasopharynx and nasal cavity is presented. A 35-year-old man admitted for nasal obstruction and visual disturbances was found to have bilateral anosmia, right homonymous hemianopsia, and a right hemiparesis. The serum prolactin level was 13,300 ng/mL. Radiological examination revealed a large mass invading the skull base and extending into the suprasellar region and the left frontal lobe superiorly and into the nasopharynx inferiorly. Subtotal removal was done through a bilateral orbitofrontal craniotomy, which was followed by radiotherapy and bromocriptine administration. Immunohistochemical analysis confirmed a prolactinoma. The rarity of such a tumor, its location and extension, and the usefulness of magnetic resonance imaging and immunohistochemistry are stressed. Pertinent literature is reviewed.

[Münchhausen syndrome with severe iron deficiency anemia]

A patient with Münchhausen syndrome who had severe iron deficiency anemia (IDA) is reported. A 31 year-old female presented with irregular genital bleeding. However, gynecological examination disclosed no evidence of specific disorders causing bleeding. Tests for bleeding tendency and hemolysis were all negative. Although massive bleeding was absent, she had three episodes of a rapid fall in Hb level associated with marked fatigue and weakness, and subsequently rapidly developed serious IDA afterwards. Factitious bleeding was strongly suspected. Blood transfusion performed when the patient was not being watched failed to increase Hb, while transfusions given while the patient was watched were effective. She was not cooperative throughout the hospital course and was discharged on her own request. In outpatient clinic, the diagnosis was confirmed by the evidence that she diluted her own blood samples.

1H-NMR assignment and secondary structure of human insulin-like growth factor-I (IGF-I) in solution

Human insulin-like growth factor-I (IGF-I) was studied by two-dimensional 1H-NMR spectroscopy. Resonance assignments were obtained for all the backbone protons and almost all of the sidechain protons of the total 70 amino acid residues, using sequence-specific assignment procedures. The secondary structure elements of human IGF-I were identified by investigation of the sequential and medium range NOEs as a preliminary step in determining the three-dimensional structure of this protein by means of distance geometry calculations. The typical NOEs of d alpha beta(i,i + 3) and d alpha N(i,i + 3), as well as the successive strong NOEs of dNN connectivities and slowly exchanging amide protons confirmed the presence of three helical segments corresponding to the sequence regions, Ala8-Cys18, Gly42-Cys48, and Leu54-Cys61, and the existence of a beta-turn in the Gly19-Gly22 region. Our results definitely indicate that the secondary structure of human IGF-I in solution is consistent with that of insulin in the crystalline state.

Ubiquitous presence in mammalian cells of enzymatic activity specifically cleaving 8-hydroxyguanine-containing DNA

Here we report the finding of enzymatic activity that specifically cleaves DNA containing 8-hydroxyguanine (oh8Gua) residues in various mammalian cells. To detect this activity, we used a synthetic double-stranded DNA containing a single oh8Gua at a defined position as the substrate, and analyzed the products of enzymatic digestion by polyacrylamide gel electrophoresis. Two cleavage sites near the oh8Gua residue were detected with partially purified fractions from cow brain and rat liver, and also with preparations from all mammalian tissues examined. These results suggest that enzymatic activity for the removal of oh8Gua from DNA is widely distributed in mammalian cells.

Inhibition of chemical carcinogenesis in vivo by azatyrosine

A single painting of 7,12-dimethylbenz[a]anthracene on the skin of transgenic mice harboring the human protooncogene c-Ha-ras induced papillomas at 100% incidence after 20 weeks (M. Izawa et al., unpublished data). Application of L-beta-(5-hydroxy-2-pyridyl)alanine (azatyrosine) to the skin at a dose of 2 mg/mouse once every 3 days after initiation with 7,12-dimethylbenz[a]anthracene greatly reduced the percentage incidence, number per mouse, and size of papillomas. Injection of methylnitrosourea i.p. into transgenic mice induced papillomas in the forestomach after 12 weeks (2 to 12 papillomas/mouse) at 100% incidence (K. Ando et al., Cancer Res., 52: 978-982, 1992). Administration of azatyrosine i.p. at a dose of 2 mg/mouse once every 2 days for 12 weeks after initiation with methylnitrosourea completely prevented the formation of forestomach papillomas. These results clearly indicated that azatyrosine inhibits chemical carcinogenesis in vivo.

Possible role of surface potential in the gating mechanism of Ca2+ channels in cat adrenal chromaffin cells: studies with fura-2 microfluorometry

The cytosolic free Ca2+ concentration ([Ca]in) in isolated cat chromaffin cells was measured by fura-2 microfluorometry. During 30 mM KCl depolarization or sucrose substitution for NaCl, a reduction in external Ca2+ concentration under optimal conditions paradoxically caused a rise in [Ca]in and, in separate experiments, in catecholamine secretion. The results support a previously suggested role of surface potentials in the gating mechanism of Ca2+ channels.

A glutamic acid residue at position 31 of Ras protein is essential to the signal transduction for neurite outgrowth of PC12 cells and the stimulation of GTPase activity by GAPRas

The roles of residues at positions 23-31 adjacent to the 'effector region' and residues at positions 61-65 in a phosphoryl binding loop of the human c-Ha-ras protein were studied by changing each residue of the normal (Gly-12 type) and oncogenic (Val-12 type) Ras proteins to the corresponding residue of the K-rev-1 protein. Firstly, the signal-transducing activities of the mutant Ras proteins of Val-12 type were examined by analysis of their ability to induce neurite outgrowth of phaeochromocytoma (PC12) cells upon expression of the mutant ras gene. Thus, replacement of Glu-31 by Lys was found to impair the signal-transducing activity of the oncogenic Ras protein. Furthermore, it was shown that expression of the Gly-12----Val/Glu-31----Lys mutant Ras protein in PC12 cells suppresses neurite outgrowth induced either by microinjection of the oncogenic Ras protein or by addition of nerve growth factor to the medium. As for the Glu-31----Lys mutant Ras protein (Gly-12 type), the GTPase activity in the presence of GTPase-activating protein for Ras (GAPRas) is much lower than that of the normal Ras protein, whereas the intrinsic GTPase activity is nearly the same as that of the normal Ras protein. Therefore, Gly-31 is one of the determinants for the signal transduction and the correct interaction with GAPRas. On the other hand, the GTPase activity of the Gln-61----Thr mutant Ras protein (Gly-12 type) is negligibly low both in the absence and in the presence of GAPRas.

[Pharmacokinetic, bacteriological, and clinical studies on panipenem/betamipron in children]

Pharmacokinetic, bacteriological and clinical studies were performed on panipenem/betamipron (PAPM/BP) in children. The results are summarized as follow: 1. Twelve patients with various bacterial infectious diseases were treated with PAPM/BP. Each dose was 20 mg/20 mg/kg, administered 3 times daily, in 30-minute intravenous drip infusion. Treatments were continued for 5-22 days. Clinical efficacies of PAPM/BP in 12 patients with bacterial infections (1 with suspected sepsis, 5 with pneumonia, 1 with acute maxillary sinusitis, 2 with acute otitis media, 1 with cervical abscess and 2 with urinary tract infection complexed type) were evaluated as excellent in 7, good in 4 and fair in 1, with an efficacy rate of 91.7%. Seventeen causative organisms found in 10 patients (Haemophilus influenzae in 4, Branhamella catarrhalis in 3, Streptococcus pneumoniae in 2, Pseudomonas aeruginosa in 2, Staphylococcus aureus in 1, alpha-Streptococcus in 1, Corynebacterium sp. in 1, Peptostreptococcus micros in 1 and Klebsiella pneumoniae in 2) were eradicated except 2 strains (S. aureus and P. aeruginosa) from 1 patient (patient No. 2). No adverse reactions were observed in any of the 12 patients. 2. MICs of PAPM were examined against 22 clinical isolates (H. influenzae 5, B. catarrhalis 3, alpha-Streptococcus 3, S. pneumoniae 2, Corynebacterium sp. 2, S. aureus 1, P. aeruginosa 1, P. micros 1, Enterobacter cloacae 1, Escherichia coli 1, Group D Streptococcus 1 and Staphylococcus epidermidis 1) from children with bacterial infections. PAPM showed a good antibacterial activity comparable to the activity of cefoperazone (CPZ) against S. pneumoniae strains relatively tolerant to penicillins. However, the activity of PAPM against H. influenzae was somewhat weaker than that of CPZ. 3. Pharmacokinetic studies.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence that the ras oncogene-encoded p21 protein induces oocyte maturation via activation of protein kinase C

The ras oncogene-encoded p21 protein is known to induce cell maturation of Xenopus laevis oocytes and malignant transformation of NIH 3T3 mouse fibroblasts. The pathways involved in oocytes and NIH 3T3 cells appear to be similar to one another. For example, in both cases, the ras p21-induced cellular events involve increased intracellular levels of the second messengers diacylglycerol and inositol phosphates, the former of which activates protein kinase C (PKC). To investigate the pathway of ras-induced oocyte maturation, we have explored the relationship between p21 protein and PKC. We show that the maturation signal from oncogenic p21 microinjected into Xenopus oocytes is completely blocked by the relatively specific PKC inhibitor CGP 41251, a staurosporine analogue that selectively inhibits PKC, but not by an inactive analogue of staurosporine, CGP 42700. Microinjection of purified PKC or of phorbol ester induces maturation of oocytes. PKC-induced maturation is inhibited by CGP 41251 but not by CGP 42700. Maturation induced by microinjected PKC is also not inhibited by two specific anti-p21 agents, the inactivating anti-p21 monoclonal antibody Y13-259 and the amino acid derivative azatyrosine. Both of these agents block p21-induced cell maturation. These results suggest that ras effects depend upon the action of PKC, whose activation is an event that occurs downstream of p21 in the maturation signal pathway.

[A retrospective comparison study of patients old and young with non-Hodgkin's lymphoma]

One hundred patients with diffuse non-Hodgkin's lymphoma were treated with combination chemotherapy including adriamycin. Seventy-one patients were under age 70 and 29 were 70 years or older. The clinical characteristics of the two groups were similar, except that the patients showed elevated serum BUN were in the elderly group. The complete remission rate in the elderly patients (66%) was slightly lower than that in the younger patients (75%) (p = NS). The average length of survival in the elderly patients was significantly shorter than in the younger patients (p less than 0.05) (projected 5-year survival: 28 +/- 11% vs 52 +/- 7%). The duration of remission for all patients in the elderly patients did not differ from that in the younger patients (projected 2-year survival: 40 +/- 10% vs 45 +/- 6%). Death during the induction chemotherapy from causes other than lymphoma occurred in 14% of patients over 70-year-old and in one percent of younger patients. At relapse, the response rate was significantly lower in the elderly patients than in the younger patients (CR+PR: 28% vs 78%, p = 0.03). To prevent toxic death in remission induction therapy, drug dose elderly patients should be attenuated according to their general conditions and performance status.

Correlation of L-myc RFLP with metastasis, prognosis and multiple cancer in lung-cancer patients

For further study of the correlation of L-myc restriction-fragment-length polymorphism (RFLP) and metastasis of lung cancer to lymph nodes or other organs at the time of surgery, L-myc RFLP was analyzed in 252 Japanese lung-cancer patients. A close correlation between L-myc RFLP and metastasis was confirmed in this large number of patients (p = 0.01). The correlation was particularly pronounced in cases of adenocarcinoma and squamous-cell carcinoma. Poor prognosis (additional metastases after surgery) was observed in lung-cancer patients with L-S (identified as long and short bands produced with EcoRI) and S-S type L-myc RFLP. In addition, the death rate of lung-cancer patients with the L-S and S-S types was greater than that of those with the L-L type. Lung-cancer patients of the L-S and S-S types had almost 4 times higher incidence of multiple cancer in the lung, pharynx and other organs than those with the L-L type. Our results indicate that, in patients with lung cancer, genetic disposition with respect to the L-myc gene influences the extent of metastasis, the incidence of multiple cancers and prognosis.

Quantification of left ventricular performance during transient coronary occlusion at various anatomic sites in humans: a study using tantalum-178 and a multiwire gamma camera

To study the functional significance of transient coronary occlusion on systolic and diastolic left ventricular function relative to the anatomic site of occlusion, first-pass radionuclide angiography with a mobile multiwire gamma camera using tantalum-178 (dose activity less than or equal to 84 mCi/elution) was performed in 46 patients undergoing balloon coronary angioplasty. First-pass images were acquired immediately before angioplasty and during the last 30 s of a 60-s balloon inflation in 23 left anterior descending arteries, 18 right coronary arteries, 8 circumflex arteries and 3 diagonal coronary arteries. Occlusion of the left anterior descending artery resulted in significant decreases in left ventricular ejection fraction (54.6 +/- 12.7% to 32.3 +/- 10.6%, p = 0.0001) and peak filling rate (2.48 +/- 0.68 to 1.75 +/- 0.64 end-diastolic volumes/s, p = 0.0001), accompanied by severe abnormalities in regional function and left ventricular dilation. Right coronary artery occlusion caused inferior hypokinesia, but did not significantly change left ventricular ejection fraction (48.5 +/- 12.4% vs. 45.8 +/- 12.5%, p = NS) or peak filling rate (2.05 +/- 0.81 vs. 2.09 +/- 0.81 end-diastolic volumes/s, p = NS). Circumflex artery occlusion resulted in mild wall motion deterioration and a borderline decrease in ejection fraction (54.7 +/- 11.4% to 50.5 +/- 12%, p = 0.057). Diagonal artery occlusion did not cause significant changes in left ventricular ejection fraction or filling rate. The decrease in left ventricular ejection fraction during coronary occlusion was 9 +/- 25% and 27 +/- 22%, respectively, in those arteries with and without collateral supply (p = 0.052). These data provide strong evidence for the critical importance of the left anterior descending artery and the secondary role of the other coronary arteries in maintaining global systolic and diastolic left ventricular function and suggest a protective role of collateral vessels during coronary occlusion.

[Embolization for traumatic carotid cavernous sinus fistula using platinum coil]

We treated a patient with a traumatic carotid-cavernous fistula (CCF) by embolization using a Tracker catheter and platinum coils by transarterial and transvenous approaches. A 65-year-old female sustained an injury in the right frontal region of the head in April, 1989. After 1 month, she was admitted to our hospital due to exophthalmos, congestion of the palpebral conjunctiva, ptosis, and a bruise in the right frontal region of the head. Right carotid angiography showed a CCF between the anterior ascending segment and the horizontal segment that drains into the superior ophthalmic vein, superior petrosal sinus and inferior petrosal sinus. To occlude the fistula, embolization was performed twice using platinum coils. In the first embolization, the cavernous sinus was approached transarterially and transvenously using a Tracker catheter system, and a total of 7 platinum coils were used for the embolization. The bruise disappeared immediately after embolization but recurred 3 days after the operation. Angiography demonstrated re-communication of the CCF. The second embolization was initially performed using a detachable balloon, but the balloon could not be passed through the fistula. Therefore, a Tracker catheter was advanced to the fistula transarterially and embolization was performed using 3 platinum coils. The fistula was occluded. Follow-up angiography after 1 year in August, 1990 showed complete occlusion of the fistula. The detachable balloon system was recently introduced in neurological and radiological departments, as a new surgical method for CCF. At present, this method is the first choice for CCF. However, the detachable balloon system presents some technical problems.(ABSTRACT TRUNCATED AT 250 WORDS)

[B-cell chronic lymphocytic leukemia complicated by autoimmune thrombocytopenic purpura]

A 74-year-old Japanese male was admitted because of anemia. Hepatosplenomegaly, lymphoadenopathy, and purpura were not found. The laboratory data on admission revealed that the white-cell count was 9,400/microliters, the hemoglobin 11.1 g/dl, and the platelet count 17,000/microliters. Platelet-associated IgG was 794.2 ng/10(7) cells. The patient was diagnosed as having autoimmune thrombocytopenic purpura (ATP) at this time. He was treated with prednisolone, but his thrombocytopenia not improve. In addition to prednisolone, azathioprine was given to him. During the course of treatment, leukocytosis gradually appeared and the white-cell count reached more than 30,000/microliters with over 70% lymphocytes. A bone marrow aspiration revealed 70% of small lymphocytes, and surface marker analysis showed that CD19 and HLA-DR were positive on these lymphocytes. Southern blotting analysis demonstrated rearrangements of JH and JK. He was finally diagnosed as B-CLL complicated by ATP. One month after the azathioprine administration, the platelet count increased more than 30,000/microliters and the white-cell count decreased less than 10,000/microliters. About 2% of patients with CLL are known to be complicated by ATP. To our knowledge, the present case is the first case of B-CLL complicated by ATP in Japan.

A muscarinic receptor agonist mobilizes Ca2+ from caffeine and inositol-1,4,5-trisphosphate-sensitive Ca2+ stores in cat adrenal chromaffin cells

To gain some understanding of the characteristics of intracellular Ca2+ stores of cat adrenal chromaffin cells, we investigated the effects of ryanodine, a blocker of Ca(2+)-induced Ca2+ release channels in muscle, on both cytosolic Ca2+ concentration and catecholamine secretion induced by caffeine or methacholine. The results suggest that Ca2+ stores consist of at least two compartments, one which is sensitive to both caffeine and inositol-1,4,5-trisphosphate (IP3), and the other which is sensitive to IP3 alone.

8-Hydroxyguanine, an abundant form of oxidative DNA damage, causes G----T and A----C substitutions

Mutations caused by oxidative DNA damage may contribute to human disease. A major product of that damage is 8-hydroxyguanine (oh8Gua). Because of differences in experimental design, the base pairing specificity of oh8G in vivo is not completely resolved. Here, oh8dGTP and DNA polymerase were used in two complementary bacteriophage plaque color assays to examine the mutagenic specificity of oh8Gua in vivo. The first is a reversion assay that detects all three single-base substitutions caused by misreading of guanine analogues inserted at a specific site. oh8Gua at that site gave a mutation frequency of 0.7%. Twenty-two of the 23 mutations were G----T substitutions. The second assay, a forward mutation assay, tests the mispairing potential of any altered nucleotide 1) during incorporation as substrate nucleotide, and 2) after multiple incorporations into a single-stranded DNA gap region of M13mp2. Substituting oh8dGTP for dGTP during polymerization produced 16% mutants; two classes of mutations were observed, both caused by pairing of oh8Gua with A. Seventy-six of 78 mutations were A----C substitutions, and two were G----T substitutions. These assays thus illustrate mutagenic replication of oh8Gua as template causing G----T substitutions and misincorporation of oh8Gua as substrate causing A----C substitutions, both caused by oh8Gua.A mispairs.

Goodpasture's syndrome: a report of an autopsy case and a review of Japanese cases

A 75-yr-old man was admitted because of acute renal failure. On the 9th hospital day, pulmonary hemorrhage occurred. He was treated with a bolus dose of methylprednisolone and plasma exchange, but died from respiratory failure on the 16th hospital day. Autopsy findings demonstrated marked intraalveolar hemorrhage and crescentic glomerulonephritis. Linear depositions of IgG along both alveolar and glomerular basement membranes (GBM) were shown by direct immunofluorescent studies. Circulating anti-GBM antibodies were demonstrated by indirect immunofluorescent techniques. This is a confirmatory case of Goodpasture's syndrome, which is rare in Japan. A review of the Japanese literature revealed some characteristics of Japanese cases.

Protection of DNA damage by dietary restriction

Dietary restriction is known to retard the aging processes and delay the onset of age-related neoplastic diseases. The mechanisms underlying these remarkable actions of nutritional intervention are not known in spite of recently intensified research efforts. However, the last couple of years' research on dietary restriction produced strong evidence indicating that its effective antiaging actions might be related to its ability to modulate free radical damage. In the present study, DNA damage and attenuation of the damage by dietary restriction were assessed by measuring 8-hydroxydeoxyguanosine 8-OH dG) in both nuclear DNA (nuDNA) and mitochondrial DNA (mitDNA) fractions. The data show that substantially more damage (approximately 15 times) occurred in mitDNA compared to nuDNA. More interestingly, the DNA damage was significantly attenuated in dietarily restricted rats.

[Thermal regulation disturbance in severely handicapped patients--the second report]

Thirty-three severely handicapped patients were investigated on body temperature regulation by rectal temperature monitoring and hypophyseal hormonal function. The lowest body temperature in the day in the cases with handicaps of prenatal onset tended to be lower than that of peri or postnatal onset. This finding suggests that different causes make regulation disturbance of body temperature in handicapped children. On the other hand, low urine osmolarity in the morning and irregular menstruation were recorded suggesting hypothalamic dysfunction in poor regulation cases.