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Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 19 recordsLinked to original sources
PubMed1992

Elongation factor-1 alpha gene determines susceptibility to transformation.

Elongation factor-1 alpha (EF-1 alpha), an essential component of the eukaryotic translational apparatus, is a GTP-binding protein that catalyses the binding of aminoacyl-transfer RNAs to the ribosome. Expression of the EF-1 alpha gene decreases towards the end of the lifespans of mouse and human fibroblasts, but forced expression of EF-1 alpha prolongs the lifespan of Drosophila melanogaster. Eukaryotic initiation factor-4E, another component of the translational machinery, is mitogenic or oncogenic when constitutively expressed in some mammalian cells. Thus, components of the protein synthesis apparatus seem to be involved in the control of cell proliferation. Using expression cloning, we have isolated a complementary DNA clone from a BALB/c 3T3 mouse fibroblast variant, A31-I-13 (ref. 10), which specifies a factor determining the susceptibility of BALB/c3T3 to chemically and physically induced transformation. Here we report that the factor is EF-1 alpha and that its constitutive expression causes BALB/c 3T3 A31-I-1 (ref. 10), C3H10T1/2 (ref. 11) and Syrian hamster SHOK fibroblasts to become highly susceptible to transformation induced by 3-methylcholanthrene and ultraviolet light. EF-1 alpha messenger RNA is also constitutively expressed in a quiescent culture of the highly susceptible variant A31-I-13. We conclude that the removal of regulation of the expression of these components of the translational machinery may predispose cells to become more susceptible to malignant transformation.

3T3 Cells↗
PubMed1992

A marine algal Na(+)-activated ATPase possesses an immunologically identical epitope to Na+,K(+)-ATPase.

Immunological homology was investigated between Heterosigma akashiwo (a marine algae) Na(+)-activated ATPase and animal Na+,K(+)-ATPase. The former polypeptide [(1989) Plant Cell Physiol. 30, 923-928] reacted with anti-serum raised against the amino-terminal half of the pig kidney Na+,K(+)-ATPase alpha subunit. It is suggested that the Na+,K(+)-ATPase epitope within the amino-terminal region is conserved in the plant Na(+)-activated ATPase, and the region containing the epitope may be important for Na ion transport.

Antibodies↗
PubMed1992

Annual changes in levels of plasma LH and size of cloacal protrusion in Japanese quail (Coturnix coturnix japonica) housed in outdoor cages under natural conditions.

Japanese quail of the strain used in our laboratory do not show a complete decrease in levels of circulating luteinizing hormone (LH) concentrations and show no collapse of the testes following their transfer from long to short days under laboratory conditions. Thus, merely manipulating photoperiods in the laboratory does not simulate an annual breeding cycle. To see whether an annual breeding cycle does exist in "our" quail under natural conditions, mature male birds were housed in individual cages and placed on the roof of a building at 35 degrees 45'N, 139 degrees 53'E; day length and ambient temperature were not controlled at all though food and water were continuously supplied. For 16 months blood was collected every week and the area of the cloacal protrusion measured at the time of each blood collection. The results showed that levels of plasma LH and the area of the cloacal protrusion had a clear annual cycle under the natural conditions. To detect more precisely the changes in circulating LH concentrations during spring and autumn, samples were collected every other day. The first significant increase in levels of plasma LH was found when the day length exceeded 12-12.5 hr, though the increase was sporadic and not synchronized among individuals. The results also showed that circulating levels of LH declined significantly in early September starting when the day length was still about 14 hr; this downward trend continued rather steadily to nonbreeding levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1992

Termination of LH secretion in Japanese quail due to high- and low-temperature cycles and short daily photoperiods.

Mature male Japanese quail were transferred from 16L:8D (19 degrees) to one of the following combinations of daily light-dark and temperature cycles, 8L:16D (12 hr, 19 degrees:12 hr, 9 degrees), 12L:12D (12 hr, 19 degrees:12 hr, 9 degrees) and 12L:12D (16 hr, 19 degrees:8 hr, 9 degrees). The low temperature is for the middle of the dark period in each treatment. In the control groups, birds were transferred to the same photoperiodic conditions as the experimental groups, but without changes in ambient temperature. Blood samples were collected every other day for 30 days and circulating levels of plasma LH were estimated by radioimmunoassay. Both the change in conditions from 16L:8D to 8L:16D with the temperature lowered for 12 hr and that from 16L:8D to 12L:12D with temperatures lowered in one case for 12 hr and in the other for 8 hr caused a lowering in plasma LH levels in all the birds to reproductively quiescent levels. The cloacal protrusion of all these birds regressed completely. In control groups, however, most if not all the birds remained in active breeding states although the levels of circulating LH decreased to basal breeding levels of 1-2 ng/ml. The results indicated that in addition to a change from long to short days an alternation of high and low temperatures was sufficient supplementary information in causing termination of LH secretion and inducing regression of the gonads and the accessory sex organs in this species.

Animals↗
PubMed1992

Stress-induced changes in brain Met-enkephalin, Leu-enkephalin and dynorphin concentrations.

Methionine-enkephalin (Met-enkephalin), leucine-enkephalin (Leu-enkephalin) and dynorphin A (1-17) (dynorphin A) concentrations in discrete brain areas were determined in the mice showing behavioral changes induced by stress using radioimmunoassay (RIA). In the present experiment, we used environment-induced conditioned suppression of motility and forced swimming-induced immobility. In the environment-induced conditioned suppression of motility, Met-enkephalin concentration in the striatum and hypothalamus significantly decreased. Leu-enkephalin concentration in the hypothalamus also decreased. Dynorphin A concentration in the striatum decreased, but significantly increased in the hypothalamus and pituitary. In the forced swimming-induced immobility, Met-enkephalin concentration in the striatum significantly decreased. Leu-enkephalin concentration in the hypothalamus and pituitary significantly decreased. Dynorphin A concentration in the pituitary decreased, but significantly increased in the hypothalamus. Our results indicated that the concentrations of Met-enkephalin, Leu-enkephalin and dynorphin A in the discrete brain areas changed in two different stressful situations. These findings suggested that these peptides might modulate the behavioral changes induced by stressors.

Animals↗
PubMed1992

Effects of salt loading on glucose tolerance, blood pressure, and albuminuria in rats with non-insulin-dependent diabetes mellitus.

We studied the effects of salt loading on glucose tolerance, blood pressure, and albuminuria in rats with mild non-insulin-dependent diabetes mellitus (NIDDM). Two-day-old male Wistar Kyoto (WKY) rats were injected intraperitoneally (IP) with either 75.0 mg/kg streptozotocin (STZ) or vehicle as control. Salt loading was performed as 1% NaCl of drinking solution from 4 weeks until 12 weeks of age (estimated sodium intake: control, 3.14 +/- 0.28 mEq/d in tap-water group, 11.9 +/- 0.95 mEq/d in salt-loaded group; NIDDM, 2.93 +/- 0.16 mEq/d in tap-water group, 12.0 +/- 2.59 mEq/d in salt-loaded group). Oral glucose tolerance, glycosylated hemoglobin (GHb), and pancreatic insulin content at 12 weeks did not differ between the salt-loaded group and tap-water group in both NIDDM and control rats. Urinary sodium excretion was increased in salt-loaded groups of control and NIDDM rats, but systolic blood pressure did not differ among the groups (control, 151 +/- 6 mm Hg in tap-water group, 150 +/- 3 mm Hg in salt-loaded group; NIDDM, 152 +/- 3 mm Hg in tap-water group, 157 +/- 2 mm Hg in salt-loaded group). Urinary albumin excretion was significantly increased in salt-loaded groups (1,790 +/- 272 micrograms/d in control, 1,617 +/- 174 micrograms/d in NIDDM rats) compared with tap-water groups (691 +/- 75 micrograms/d in control, P less than .05; 616 +/- 69 micrograms/d in NIDDM rats, P less than .001), irrespective of STZ injection, but endogenous creatinine clearance was not different among the groups. Furthermore, renal growth was more greatly increased in salt-loaded groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1992

Simple in vivo bioassay without radioisotopes for recombinant human erythropoietins.

A simple in vivo bioassay suitable for routine testing of quality control of recombinant human erythropoietin (rHuEPO) analogues was developed. The assay took four days, normal mice were used and radioactive compounds were not needed. EPO activity was measured by the increased number of some part of reticulocytes which increased specifically and dose-dependently by the injection of rHuEPO. They were considered to be mostly immature reticulocytes and were counted as the residual particles from blood cells after treatment with a hemolysing reagent. These particles could be counted by conventional automated microcell counters. The assay procedure was simple and easy. The sensitivity, reliability and reproducibility of this method were acceptable for routine in vivo bioassay of rHuEPOs. This method was economical, and can be used instead of the existing bioassays for rHuEPOs.

Animals↗
PubMed1992

In vivo biological activities of recombinant human erythropoietin analogues produced by CHO cells, BHK cells and C127 cells.

The in vivo biological activity of four pharmaceutical preparations of recombinant human erythropoietin was compared. Two of the erythropoietins were produced by Chinese hamster ovary cells, CHO-K1, and the others were produced by mouse mammary cells, C127, and baby hamster kidney cells, BHK-21. The activities of the analogues were estimated by a simple cell counting method with conventional automated microcell counters. The amounts of these analogues gave straight logarithmic dose-response curves when plotted against the count of particles resistant to hemolysing reagent, which particles were mostly immature reticulocytes. The lines from the four analogues were parallel to each other. The relative activities of these analogues were 1.02, 1.19 and 1.21 when one of the analogues was arbitrarily used as the standard. These differences in the extent of the activity were not significant. Thus, the four recombinant human erythropoietin analogues, produced by four different mammalian cell lines, expressed the same biological potencies in vivo corresponding to their units, and the units used up to now by the manufacturers are equivalent. These results also draw the conclusion that the new simple in vivo bioassay can replace the existing accepted assay methods.

Animals↗
PubMed1992

Induction of ovarian growth and ovulation by administration of a chicken gonadotrophin preparation to Japanese quail kept under a short-day regimen.

1. Chronic administration of a glycoprotein fraction from chicken pituitary using an ALZET osmotic pump at 12.5 micrograms/h for 2 weeks induced growth of ovarian follicles to a mature size in the ovary and deposition of yolk in sexually immature 6-week-old Japanese quail females which were kept under 8L:16D short-day conditions. However, no ovulation was induced in these birds. 2. Injection of 500 micrograms of the glycoprotein into other immature short-day females was performed following the above chronic administration, 12 or 14 and 15 d after implantation of the osmotic pump. About 24 h after injection, 3 of 14 females laid one or two eggs. Ovulation was confirmed in 4 females by autopsy. A total of 5 of 14 females ovulated 6 eggs, and significant development of the oviduct and the cloacal opening were observed in all of the treated females. 3. Thus, complete ovarian function could be induced in sexually immature female Japanese quail by administration of avian gonadotrophin using a combination of an osmotic pump and an injection.

Animals↗
PubMed1992

Characterization of rat liver mannan-binding protein gene.

We previously found that rat liver mannan-binding protein (L-MBP) is encoded by two species of mRNA of 1.4 and 3.5 kb long. In this study, the structure of the gene encoding rat L-MBP was determined from the sequences of isolated genomic DNA clones and PCR amplified DNA fragments. Rat L-MBP is encoded by at least three species of mRNA, the differences among which are generated by an alternative splicing at the 5'-nontranslated region and an alternative utilization of polyadenylation sites. The rat L-MBP gene consists of six exons separated by five introns. The coding region of rat L-MBP mRNA is encoded by four exons (Exons III-VI), the 5'-noncoding region by Exons I and II, and the 3'-noncoding region by Exon VI. The exon-intron boundaries of L-MBP are completely identical to those of rat serum and human MBP, suggesting that all three MBPs are derived from a common ancestral gene.

Amino Acid Sequence↗
PubMed1992

Mutations of the p53 tumour suppressor gene in haematologic neoplasms.

Mutations of the p53 tumour suppressor gene have frequently been observed in several types of solid tumours and are believed to be implicated in the development of these tumours. To determine the relevance of p53 mutations in haematologic neoplasms, we performed polymerase chain reaction-single strand conformation polymorphism analysis on the p53 gene in 45 patients with various types of haematologic neoplasms. In exons 5-8 containing highly conserved regions, mobility shifts indicating sequence alterations were detected in four of the 45 patients, and subsequent sequencing was performed. A point mutation resulting in a novel stop codon was detected at codon 213 in one of 23 cases of chronic myelogenous leukaemia (one of five cases of blast crisis). Point mutations causing amino acid substitutions were detected in one of four cases of myelodysplastic syndrome at codon 195, one of three cases of adult T-cell leukaemia at codon 281, and one of eight cases of acute lymphoblastic leukaemia at codon 281, and these missense mutations were accompanied by loss of the wild type allele. Patients harbouring these nonsense and missense mutations were in advanced disease stages. These findings suggest that mutational inactivation of the p53 gene is infrequent but is involved in the tumorigenesis of several types of haematologic neoplasms at least in some cases.

Amino Acid Sequence↗
PubMed1992

Cloning and expression of the gene for the Avi-3 antigen of Mycobacterium avium and mapping of its epitopes.

The Avi-3 antigen, which is found only in Mycobacterium avium culture sonic extracts, is species specific and results in strong skin test activity in guinea pigs sensitized with heat-killed M. avium. Its gene was cloned by using a previously developed single-probe method and was sequenced. The gene encoded a 194-amino-acid polypeptide with a molecular weight of 21,500. A recombinant Avi-3 antigen expressed in Escherichia coli reacted with monoclonal and polyclonal antibodies raised against the native Avi-3 antigen. To identify epitopes on this protein for immunodiagnostic purposes, various parts of the Avi-3 antigen were expressed as beta-galactosidase fusion proteins, using pUR and pURS expression vectors. The clones screened by both antibody reactivity and T-cell proliferative activity defined fragments with coexisting B- and T-cell epitopes. A B-cell epitope (Asn-176 to Ala-186) and two T-cell epitopes (Glu-75 to Ile-86 and Arg-155 to Leu-164) were thus defined. The synthetic polymerized peptides of the T-cell epitopes were proven to elicit a delayed cutaneous hypersensitivity reaction in guinea pigs. This mapping method would be useful in the development of a subunit vaccine consisting of an immunodominant B-cell epitope linked to a T-cell epitope in the vicinity.

Amino Acid Sequence↗
PubMed1992

[Statistical study of the optimal conditions of the spiral plating method for counting bacterial numbers in river water].

The application of the spiral plating method, a rapid and labor-saving technique for enumerating bacteria in food, to evaluate bacteria in river water, was examined. Standard plate counts and the numbers of heterotrophic bacteria, coliforms and Flavobacterium spp. in the water were tested by the spiral plating method, the results were compared with those of the conventional method and the optimal conditions for using the spiral plating method were considered and selected to fit the conventional methods. The optimal conditions selected were as follows: by laser colony counter after incubation at 35 degrees C for 38h. for standard plate counts; by laser colony counter after incubation at 25 degrees C for 48h. for the numbers of heterotrophic bacteria and Flavobacterium spp.; by colony viewer counting reddish colonies > or = 0.25mm in diameter after incubation at 35 degrees C for 22h. for the number of coliforms. The numbers of bacteria, except for coliforms, determined by this spiral plating method were found to be closely related to those from conventional methods (r > or = 0.91), and the replicating variances of both methods were not significant. The counts of bacteria by laser colony counter gave results similar to those by colony viewer counting by visual inspection. This spiral plating method saved time, money and labor in the evaluation of bacteria in river water as comparable to that in food. These results indicate that the spiral plating method can be used in place of conventional methods in evaluating the number of bacteria in river water.

Colony Count, Microbial↗
PubMed1992

Genetic mapping and biochemical characterization of suppressor mutations sukA and sukB for a dnaK7(Ts) mutation of Escherichia coli K-12.

Temperature-resistant pseudorevertants were isolated from a dnaK7(Ts) mutant of Escherichia coli K-12. Two of these pseudorevertants were shown to carry suppressor mutations, sukA and sukB, respectively. Genetic mapping by conjugation and P1-transduction revealed that these suppressor mutations were located at two distinct sites between 76 and 77 min close to the suhA and rpoH genes. Labeled cellular proteins were extracted from suppressor mutants grown at various temperatures and subjected to SDS-gel electrophoresis. Autoradiograms of the gels indicated that these suppressor mutations each resulted in increased synthesis of the heat shock protein Lon (an ATP-dependent protease, La) at both permissive and nonpermissive temperatures.

Bacterial Proteins↗
PubMed1992

Effects of removal of chicks from hens on concentrations of prolactin, luteinizing hormone and oestradiol in plasma of brooding Gifujidori hens.

Gifujidori hens were allowed to repeat a breeding cycle in one season. In the first breeding cycle the duration of the brooding (raising chicks) stage was limited to 3 weeks, whereas in the second breeding cycle it was limited to 1 week by removing all chicks from mother hens. In the first breeding cycle, plasma prolactin (PRL) was high during the incubation period, but rapidly decreased on the day of hatching and reached minimum values about 1 week after hatching. In contrast, plasma luteinizing hormone (LH) concentrations were low during the incubation period, but after hatching they gradually increased and reached peak values immediately after removal of chicks. Concentrations of oestradiol in plasma were low in the incubation and brooding stages but increased significantly immediately after removal of chicks. In the second breeding cycle, changes in PRL and LH concentrations were similar to those observed in the first breeding cycle except that even greater increases in plasma LH and oestradiol concentrations were observed one week after hatching when the chicks were removed. These results suggest that coexistence of newly hatched chicks may suppress LH secretion from the pituitary of the hen in the natural breeding cycle.

Animals↗
PubMed1992

Mesenchymal hamartoma of the liver: report of an adult case and review of the literature.

A case of mesenchymal hamartoma of the liver incidentally found to be a hyperechoic mass by abdominal ultrasonography in a 62-year-old male is described. Computed tomography and magnetic resonance imaging of the liver confirmed the presence of a well-demarcated inhomogeneous mass in the left medial segment. Hepatic arteriography revealed the mass to be generally hypovascular. Histopathologic diagnosis of the resected specimen was a solid form of benign mesenchymal hamartoma, a rather rare lesion for the patient's age. Fifteen adult cases of hepatic mesenchymal hamartoma in the literature including the present case are reviewed.

Diagnosis, Differential↗
PubMed1992

Effects of vitamin B12-deficiency on testes tissue in rats.

The state of vitamin B12-deficiency in rats was evaluated by determination of hepatic vitamin B12-dependent enzyme activities after the animals had fed on a vitamin B12-deficient soybean protein diet for 150 days. The effect of vitamin B12-deficiency on testicular tissue was also studied by morphological observations. Growth of vitamin B12-deficient rats was retarded and marked increase in urinary methylmalonic acid was observed. Vitamin B12 contents in the organs were depressed distinctly by the deficiency, especially in testes, vitamin B12 content decreased to 2.5 ng/g. Hepatic methionine synthase and methylmalonyl-CoA mutase activities showed striking depression to 5% of the control rats and extreme vitamin B12-deficiency was confirmed. Testes weight also showed marked decrease together with their relative weight per 100 g body weight. Morphological observations of testes of vitamin B12-deficient rats revealed atrophy of the seminiferous tubules and aplasia of sperms and spermatids. The above results proved that vitamin B12-deficiency affected rat testes, and suggested that the rat could be the animal model for elucidation of the mechanism of B12 action on testicular functions.

Animals↗