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Biomedical subjects

A Kojima

Publications and source records attributed to A Kojima.

At least 253 records · Page 14Linked to original sources
PubMed1988

The effect of thymectomy on the development of nephropathy in spontaneous thymoma rats of the BUF/Mna strain.

A close relationship was assumed between the developments of nephropathy and thymoma in the previous study, in which the effect of introduction of the rat nude gene was studied in high thymoma BUF/Mna rats. In this paper, the effect of neonatal thymectomy on the development of nephropathy was examined to clarify the relationship between these two lesions in BUF/Mna rats. The average amount of urinary protein excreted from sham-operated and thymectomized BUF/Mna rats was 30.8 +/- 17.1 and 40.0 +/- 20.0 mg/day, respectively, and the number of affected glomeruli per 100 glomeruli 4.9 +/- 1.0 and 5.3 +/- 2.0, respectively. There were no significant differences in the urinary protein content, the number of the affected glomeruli, and immunofluorescence findings. In a control group, ACI/NMs rats exhibited 8.9 +/- 2.6 mg/day protein in urine and 0.8 +/- 0.4% affected glomeruli, which were significantly different from that of sham-operated and thymectomized BUF/Mna rats. These results indicate that nephropathy in BUF/Mna rats results neither from thymoma itself nor from the immunological abnormality secondary to it, and suggest that this lesion might be ascribed to a genetic factors.

Animals↗
PubMed1988

A new mutation involving the sublingual gland in NFS/N mice. Partially arrested mucous cell differentiation.

A new mutation in mice affecting the mucous cell differentiation of the sublingual glands is described. The normal mouse sublingual glands are mucus-secreting and virtually all the acinar cells differentiate to mucus-rich cells by the day of birth. In contrast, all endpieces of newborn mutant mice consisted of acini of immature cuboidal cells. However, normal mucous cells, staining intensively with mucin-specific stains such as Alcian blue at pH 2.5 or mucicarmine, appeared in the mutant mice from an early age singly or in groups in a small number of acini, and their number apparently increased with age to occupy over 30% of the total acinar cells. Ultrastructurally, irregular secretion granules of varying electron-density, distinct from ordinary sublingual mucin granules, were frequently observed in the cytoplasm of the immature acinar cells in the mutant phenotype. The genetic analysis showed that a single autosomal recessive gene determined the observed abnormality. This is the first salivary gland mutation and will provide a critical model for the study of salivary mucous cell differentiation.

Aging↗
PubMed1987

Simultaneous multivessel coronary artery spasm demonstrated by quantitative analysis of thallium-201 single photon emission computed tomography.

Thallium-201 myocardial scintigraphy with quantitative analysis of emission computed tomography was performed during episodes of angina in 19 patients with variant angina and nearly normal coronary arteriographic findings. Eleven patients (group I) were shown by arteriography to have spasm in 2 or more large coronary arteries. Eight patients (group II) had spasm in only 1 coronary artery. In 7 patients in group I, significant diffuse perfusion defects simultaneously appeared in multiple coronary artery regions on the scintigram (group IA). The extent and severity of the perfusion defect as measured by thallium-201 tomography were significantly greater in group IA than in group II (p less than 0.001 and p less than 0.01, respectively). The duration of transient ST-segment elevation during the attack in group IA was significantly longer than in group II (p less than 0.001). The incidence of ventricular arrhythmias, including ventricular tachycardia, or complete atrioventricular block during the anginal attack was significantly higher (p less than 0.05) in group IA than in group II. In all study patients, neither attack nor scintigraphic perfusion defect appeared on the repeat test after oral administration of nifedipine. In conclusion, multivessel coronary artery spasm simultaneously appears and causes the attack in many patients with variant angina and nearly normal coronary arteriographic findings, and myocardial ischemia due to simultaneous multivessel coronary spasm is likely to be more extensive and severe, persist longer and have a higher frequency of potentially dangerous arrhythmias than that due to spasm of only 1 coronary artery.

Angina Pectoris, Variant↗
PubMed1987

Recombinant vaccinia virus LC16m0 or LC16m8 that expresses hepatitis B surface antigen while preserving the attenuation of the parental virus strain.

Thymidine kinase-negative recombinant vaccinia virus LC16m0 or LC16m8 expressing hepatitis B surface antigen preserved almost the same pathogenicity as their parental thymidine kinase-positive attenuated virus strains. The results demonstrate the potential for using the LC16m0 or LC16m8 virus strain as a vector for recombinant vaccine.

Animals↗
PubMed1987

Possible single dosage effects of the nude gene: suppression of spontaneous development of thymoma and nephropathy in BUF/Mna-rnu/+ rats.

Single dosage effects of the rat nude gene (rnu) on spontaneous development of epithelial thymoma, muscle atrophy and nephrotic syndrome were studied by comparing littermates of rnu /+ and +/+ rats on a high thymoma strain, BUF/Mna, background. Heterozygous rnu/+ rats had a significantly smaller thymus than the +/+ littermates at 6 weeks of age. The incidence of thymoma at 12 months of age was extremely low in the female rnu/+ rats (3%) as compared with that of the +/+ rats (94%). Development of the nephrotic syndrome but not of the muscle atrophy was also suppressed in the heterozygotes. The results suggest that a recessive mutant gene, rnu, in a single dosage, interfered with critical steps of the disease processes of the thymoma and nephrotic syndrome in BUF/Mna-background rats.

Animals↗
PubMed1987

[Combined treatment of irradiation and 8 MHz radiofrequency hyperthermia with chemoembolization in advanced renal tumor].

A combined treatment of irradiation and 8 MHz radiofrequency hyperthermia after chemoembolization, using 20 mg of microencapsulated mitomycin C (MMC.mc), was undertaken in a patient with an advanced left renal tumor. The patient, a 70-year-old man, noticed a gross hematuria in February, 1984. CT showed a left renal tumor, 88 X 70 mm in size. Histological examination revealed clear cell carcinoma of the left kidney. The tumor was unresectable because of an invasion into the surrounding tissues. Chemoembolization was performed before the combined treatment of irradiation and hyperthermia. He received 23.2 Gy of irradiation and 10 sessions of hyperthermia. Intratumoral temperature reached 42.6 degrees C during the heating. After treatment, there was a tumor regression rate of 58%, as well as pain relief, and an improvement in his appetite loss. He died 8 months after this treatment. An autopsy specimen revealed bionecrotic tumor cells among the prominent necrotic and fibrotic tissues.

Aged↗
PubMed1986

Effects of propranolol and nifedipine on exercise-induced attack in patients variant angina: assessment by exercise thallium-201 myocardial scintigraphy with quantitative rotational tomography.

To examine the effects of propranolol and nifedipine on exercise-induced attack in patients with variant angina, exercise 201Tl myocardial scintigraphy with quantitative analysis by emission-computed tomography was performed in 20 patients with variant angina after oral propranolol (80 mg), nifedipine (20 mg), and placebo. Exercise-induced attack occurred in 11 patients on placebo, in 14 on propranolol, and in none on nifedipine. The exercise duration was significantly shorter in those on propranolol (p less than .05), but significantly longer in patients on nifedipine (p less than .05) than in those on placebo. The peak rate-pressure product was significantly lower in patients on propranolol (p less than .01), but did not change in those on nifedipine, as compared with that in patients on placebo. The size of the perfusion defect as measured by 201Tl tomography was significantly greater in patients on propranolol (p less than .05), but significantly less in those on nifedipine (p less than .01) than in those on placebo. In conclusion, propranolol does not suppress but rather may aggravate exercise-induced attack in patients with variant angina, while nifedipine suppresses it. This unfavorable effect of propranolol on exercise-induced attack in patients with variant angina is likely to be due to a reduction of regional myocardial blood flow.

Adult↗
PubMed1986

Accelerating effect of nude gene heterozygosity on spontaneous AKR thymic lymphomagenesis.

The effect of nude gene heterozygosity on spontaneous AKR thymic lymphomagenesis was studied by comparing female littermates of AKR/Ms-nu/+ and +/+. As previously reported in nude gene heterozygotes with genetic background other than AKR, AKR/Ms-nu/+ mice had a significantly smaller thymus than the +/+ littermates. Overall incidences of thymic lymphomas were comparable in the two genotypes, but the mean latent period for lymphoma development was significantly shorter in the nu/+ mice (266.3 +/- 11.6 days) than in the +/+ mice (319.3 +/- 7.9 days). Both genotypes of mice expressed a high level of XC+-ecotropic murine leukemia virus. Expression of xenotropic virus was more variable, but there was no consistent difference in onset of virus expression or in virus titer that could explain accelerated lymphomagenesis in the nude gene heterozygotes.

Animals↗
PubMed1986

Paradoxical effect of three-day thymectomy on sarcogenesis in the mouse with different dosages of methylcholanthrene.

Past studies have shown that thymectomy in the mouse at 3 days of age but not at birth or after 7 days produces, in later life, a variety of localized autoimmune lesions. In the present work, 3-day thymectomy facilitated subsequent sarcogenesis by low dosages of 3-methylcholanthrene but inhibited oncogenesis by a high dosage. If the presence of autoimmunity implies an increased antitumor immunity, it then follows that increased immunity facilitated low-dose sarcogenesis but inhibited sarcogenesis with a high dose.

Age Factors↗
PubMed1986

[Three cases of primary aldosteronism including one case with postoperative ventricular tachycardia].

Three patients with primary aldosteronism were treated surgically between February and September 1984. All patients had suffered from hypertension with U waves in ECG and laboratory examinations revealed hypokalemia, hyperaldosteronemia and suppressed plasma renin activity. The localization of the adrenal tumor was diagnosed accurately in all 3 patients by adrenal vein sampling and in 2 of the patients by PRP, CT scan, adrenal scanning with 131I-iodo cholesterol and adrenal venography. Adrenal tumors were surgically removed by unilateral adrenalectomy through the flank approach in all cases. Histological examinations of removed specimens showed adrenocortical adenoma. Removal of the adenoma caused a prompt reversal of the laboratory serum abnormalities and hypertension was normalized within 2 weeks postoperatively in all cases. Severe ventricular tachycardia (Torsades de Pointes) was observed suddenly in one of the patients after about 5 hours postoperatively. Therapy including conventional antiarrhythmic drugs, such as lidocaine or procainamide, and potassium administration failed to prevent the arrhythmia. Ventricular tachycardia was successfully treated and disappeared with the use of magnesium sulfate (MgSO4) intravenously. The serum potassium concentration was normal during the episode and the serum magnesium concentration, which was not detected before or just after the operation, was under the limit of normal range (1.4 mEq/l) after the use of magnesium sulfate. Hypomagnesemia which is retrospectively thought to be the result of primary aldosteronism may be responsible for the episode of postoperative ventricular tachycardia.

Adenoma↗