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Biomedical subjects

N Takagi

Publications and source records attributed to N Takagi.

At least 127 records · Page 7Linked to original sources
PubMed1995

Changes in striatal dopamine metabolism after microsphere embolism in rats.

BACKGROUND AND PURPOSE: Dopamine plays an important role in striatal function. The present study was undertaken to elucidate the pathophysiological changes in striatal dopamine metabolism after microsphere embolism. METHODS: Microspheres (48 microns) were injected into the right internal carotid artery of rats. Extracellular levels of dopamine and its metabolites were measured by in vivo microdialysis with the aid of high-performance liquid chromatography. In vivo striatal tyrosine hydroxylation and turnover (catabolism) rate of dopamine were estimated on the first and third days after the embolism. These were estimated by measuring tissue dopa or dopamine content in the presence of either an aromatic L-amino acid decarboxylase inhibitor or a tyrosine hydroxylase inhibitor, respectively. RESULTS: In the microdialysis study, a 190-fold increase in the release of dopamine from the right striatum was observed 40 minutes after microsphere embolism, whereas the striatal dopamine metabolites decreased during the first 180 minutes after the embolism. Microsphere embolism decreased the striatal dopamine content throughout the experiment (28 days), whereas it increased tissue dopamine metabolites on the first day, followed by a decline in the metabolites on the third day or later. The in vivo turnover rate of dopamine decreased both on the first and third days, whereas the in vivo tyrosine hydroxylation decreased only on the third day after the embolism. CONCLUSIONS: The results suggest that microsphere embolism induces severe damage to striatal dopaminergic metabolism 3 to 28 days after the embolism. Dopamine synthesis may be more resistant to the embolism-induced ischemic insults than its catabolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1995

Expression of tumor necrosis factor receptors in human lung cancer cells and normal lung tissues.

The purpose of this study was to investigate the expression of tumor necrosis factor (TNF) receptors for the control of the biologic action of TNF-alpha in lung cancer cells and normal lung tissues. Lung cancer specimens and normal lung tissues were freshly obtained in pairs from 15 patients who underwent surgery for lung cancer. Thirteen lung cancer specimens expressed the 55 kDa TNF receptor messenger RNA (mRNA), whereas only six lung cancer specimens expressed the 75 kDa TNF receptor mRNA by Northern blot analysis. The 55 kDa and 75 kDa TNF receptors mRNA were detected in all and 11 normal lung tissues, respectively. All four lung carcinoma cell lines examined expressed the 55 kDa TNF receptor mRNA, but only RERF-LC-MS (MS) expressed both the 55 kDa and 75 kDa TNF receptors mRNA. Immunohistochemical examination revealed that lung cancer cells expressed the 55 kDa TNF receptor, but not the 75 kDa TNF receptor at the protein level. In normal lung tissues, the 55 kDa TNF receptor was detected in alveolar macrophages, bronchioles, and some small vessels. The 75 kDa TNF receptor was detected in alveolar macrophages. All four lung carcinoma cell lines examined exhibited the only 55 kDa TNF receptor. TNF-mediated tumor cell lysis was observed in all lung carcinoma cell lines that exhibited the 55 kDa TNF receptor except A549, which is a TNF-insensitive cell line. In surface binding assays, specific surface binding of TNF-alpha to TNF-insensitive cell line A549 was observed to be about half that of TNF-sensitive cell lines. We demonstrated the expression of two distinct TNF receptors in human lung cancer and normal lung tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Humans↗
PubMed1995

[A case control study of risk factors for Japanese cedar pollinosis].

Risk factors for Japanese cedar pollinosis including past or family history of allergic diseases, smoking and passive smoking, dwelling conditions, and life events were analyzed by a case control method. Patients with Japanese cedar pollinosis (22 males and 67 females) were matched with a corresponding number of patients without potential symptoms of pollinosis according to sex and age (+/- 5 years). The mean age was 39 years in both groups. The odds ratio (OR) was calculated by McNemar's method and the conditional logistic regression model. The design and methodology in this study were somewhat inadequate so that the validity of the results is limited. The most important problem was no-matching according to exposure to pollen. Significantly high OR for past history of allergic disease (8.80, 95% confidence interval (CI); 3.49-22.2), atopic sermatitis (9.00, 95% CI; 1.14-71.0), and a sibling history of allergic disease (3.25, 95% CI; 1.06-9.97) were consistent with former genetical studies. ORs were lower than unity for current smokers (0.36, 95% CI; 0.11-1.13) and those smoking 10 cigarettes/day or more (0.20, 95% CI; 0.04-0.91) relative to nonsmokers. The OR for passive smoking from 7-15 years of age as a result of the father's smoking habit (0.38, 95% CI; 0.17-0.86) was also significantly low. Smoking was suggested to increase the level of total and antigen-specific IgE in serum by former studies, so that sensitization and symptoms should be studied separately. The high OR of residents in a business or light industrial area (5.00, 95% CI; 1.45-17.3) suggested an association with air pollution.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

Histological analysis of male hybrid sterility induced by the Hst-1 gene in mice.

Hybrid sterility is thought to play an important role in the differentiation and maintenance of respective biological species. In the present study, as a first step to clarify the mechanism of hybrid sterility caused by the Hst-1 gene in mice, the male sterile hybrid between C57BL/6 and M. m. musculus was investigated by histological techniques. Many spermatogonia and primary spermatocytes were observed in the testes of the hybrid sterile mice. Neither secondary spermatocytes nor spermatids were detected throughout the sections. It was noted that some spermatocytes showed degenerations in part of the lumina of the seminiferous tubules. In the chromosomal preparations of primary sterile hybrids, the percentage statistical values for the spermatogonia/leptotene stage were increased and those for the zygotene/pachytene stage were markedly decreased. Neither round nor elongated spermatids were detected throughout the preparations. It was observed that many primary spermatocytes were degenerated. These results suggest that spermatogenesis stops at the leptotene stage and that a small number of cells progress to the next meiosis, but degenerate to die during the pachytene stage.

Animals↗
PubMed1995

Detection of Pneumocystis carinii, Mycobacterium tuberculosis, and cytomegalovirus in human immunodeficiency virus (HIV)-infected patients with hemophilia by polymerase chain reaction of induced sputum samples.

The purpose of this study was to diagnose the initial stage of acute pulmonary infections due to Pneumocystis carinii (P. carinii), Mycobacterium tuberculosis (M. tuberculosis), and cytomegalovirus (CMV) by polymerase chain reaction (PCR) combined with the induced sputum method in hemophilia patients infected with human immunodeficiency virus (HIV). Induced sputum and PCR were obtained at each outpatient visit or when any respiratory symptoms were present during a one-year period. All patients with a CD4+ count of less than 200 x 10(6)/l were given prophylactics against P. carinii pneumonia (PCP). PCR was conducted 111 times in 29 patients. M. tuberculosis DNA was detected in 1 patient and CMV DNA in 4 patients. P. carinii DNA was not detected. PCR on induced sputum samples is sensitive for the rapid detection of the initial stage of respiratory events. PCP prophylaxis changes the clinical manifestations of HIV infection.

AIDS-Related Opportunistic Infections↗
PubMed1995

[Value of PSA/gamma-Sm ratio (P/S ratio) for diagnosis of prostate cancer in patients with urinary retention].

It is known that serum prostate specific antigen (PSA) in urinary retention due to benign prostatic hypertrophy (BPH) increase. To evaluate prognostic value of the ratio of serum PSA to gamma-seminoprotein (P/S Ratio) for prostate cancer (PC) in patients with urinary retention, we have studied the P/S Ratio at the initial examination in 33 patients with untreated PC (10 with and 23 without urinary retention) and 193 patients with untreated BPH (38 with and 155 without urinary retention) histopathologically diagnosed at our hospital between January, 1992 and December, 1993. The results were as follows: 1) The mean P/S ratio of PC patients was significantly higher than that of BPH patients in both groups with and without urinary retention. 2) When the cut off value of P/S Ratio was determined to be 1.35, the highest efficiency, 59.3% was obtained in the group without urinary retention. The sensitivity and specificity were 65.2% and 91.0%. 3) In the group with urinary retention, the efficiency was also the highest, 80.0% with a cut off value of 1.35. The sensitivity and specificity were 80.0% and 100%. 4) In all patients, the efficiency was 64.6%, the sensitivity was 69.7%, and the specificity was 92.7% with a cut off value of 1.35. 5) Positive rate of serum PSA in BPH patients with urinary retention was 47.4% and that in BPH patients without urinary retention was 17.4%. The mean P/S ratio of the BPH patients with urinary retention was significantly lower than that of BPH patients without urinary retention, which suggested that the serum free PSA increase in the former.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

[High flow priapism after perineal trauma, successfully treated by unilateral embolization of the internal pudendal artery: a case report].

We reported a case of 45-year-old patient with high flow priapism secondary to arteriovenous fistula produced by perineal trauma. Diagnosis was based on the results of gasometry in cavernous blood, cavernography and pudental arteriography. Although conservative treatment had been tried, complete resolution of priapism was not obtained. We could successfully treat the priapsim by percutaneous temporary embolization of the right internal pudendal artery with Gelatin. Erection and sexual function, after 2 months of treatment, was normal. The rationale for the use of this embolization in the treatment of high flow priapism and its etiology was discussed.

Embolization, Therapeutic↗
PubMed1995

[Evaluation of the efficacy of recombinant human erythropoietin (rHuEPO) administration on penile erection in males undergoing hemodialysis and effect on pituitary-gonadal function].

Recombinant human erythropoietin (rHuEPO) was administered to males undergoing hemodialysis, and its effects on penile erection and hypothalamus-pituitary-gonadal hormone levels were studied. The subject consisted of 18 males undergoing hemodialysis ranging in age from 22 to 58 years (mean 45.3 years). Chronic glomerulonephritis was present in 16, and diabetic nephropathy in 2, as underlying disease. rHuEPO was administered intravenously at 1,500 U 3 times a week with a target to increase the Ht value to 25% or above. Penile erection was evaluated subjectively by a questionnaire based on a visual analogue scale and objectively by semi quantitative measurement of nocturnal penile tumescence (NPT) using an erectometer. Of the 18 patients, subjective improvements in penile erection were observed in 13 (72%), and objective improvements in NPT were observed in 10 (56%). The administration of rHuEPO may alleviate hyperprolactinemia but was found to have no effect on the FSH, LH, Zn, or HS-PTH level. rHuEPO was suggested to be fairly effective for the treatment of sexual disorders.

Adult↗
PubMed1995

[High flow priapism following a straddle-injury-induced arteriocavernosal fistula: a case report].

A 26-year-old man with high flow priapism after blunt perineal trauma, is described herein. Patient evaluation included intracavernal blood-gasometry, cavernography, color flow Doppler sonography. The blood-gasometry showed pH 7.413, pO2 77.9 mmHg, pCO2 41.0 mmHg, HCO2- 26.1 mmol/L, BE 2.0 mmol/L. By direct cavernosography, pooling of contrast agent was seen at the root of the penis. Color flow Doppler sonography revealed pulsatile, turbulent flow within left corpus cavernosum. Our case was diagnosed as high flow priapism from these findings. Detumescence was not achieved by an alpha-adrenergic agent. Superselective embolization of the deep artery of the penis with autologous blood clot was performed with good results. Our case demonstrates that this procedure is a safe and effective therapy for high flow priapism and that erectile function can return to normal.

Adult↗
PubMed1995

Aquaretic effect of a potent, orally active, nonpeptide V2 antagonist in men.

Solute-free water diuretics (aquaretics) that antagonize hydrosmotic vasopressin 2 (V2) receptors may be useful in treating diseases in which water is retained. An orally active, nonpeptide, selective V2 antagonist (OPC-31260) was administered in six dose steps (3, 15, 30, 60, 100 and 200 mg) to six healthy, normally hydrated men to investigate the aquaretic effects in comparison with 12 placebo-treated control subjects (two at each dose). All subjects tolerated all six doses without serious clinical side effects. OPC-31260 increased the first 6-hr hypotonic urine volume dose-dependently. Administration at 30 mg raised the 6-hr urine volume to 2 times, 100 mg to 3 times and 200 mg to 4 times (1828.0 +/- 130.2 ml/6 hr) that of the placebo group (470.4 +/- 52.1 ml/6 hr). The drug increased urine flow maximally between 1 and 1.5 hr at all doses (e.g., 10.0 +/- 0.7-10.8 +/- 0.4 ml/min at 60-200 mg). The drug rapidly lowered urine osmolality for 4 hr, particularly between 60 and 90 min (e.g., 72.3 +/- 2.3 and 62.3 +/- 5.1 mOsm/kg at 100 and 200 mg, respectively). In marked hypotonic diuresis, mean free-water clearance of the 6-hr urine increased dose-proportionally into the positive range, reaching 2.82 +/- 0.21 ml/min at 200 mg.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMed1995

[A cross-sectional study of factors associated with production of Japanese cedar pollen specific IgE antibody and total IgE antibody, and symptoms of Japanese cedar pollinosis in primary school children].

Frequency of and factors associated with sensitization by Japanese cedar pollen (JCP) and Japanese cedar pollinosis (JCPS) were analyzed by a cross-sectional method. Four hundred and five primary school children in a rural town were examined by a questionnaire filled out by their parents and a serum test in May, 1994. Children with positive JCP specific IgE antibody (CAP-RAST score > = 1) comprised 39%, and those with a score of 2 or more, 35%. Prevalence of JCPS defined as positive IgE antibody and "definite symptoms" (any nasal and/or conjunctival symptom continuing for three weeks or more in March and/or April) was 8%, and that of JCPS defined as positive IgE antibody and "definite or possible symptoms" (no condition for duration) was 22%. Children with a high total IgE antibody level (> = 250 U/ml) comprised 26%. The JCP specific IgE antibody level revealed a strong positive correlation with the total IgE antibody level. Past and family history of allergic disease in general was associated with a total IgE antibody level stronger than the JCP specific IgE antibody level, and the history was also associated with allergic-like symptoms except for JCPS stronger than the symptoms of JCPS. Passive smoking by family and use of kerosene stove were negatively associated with the highest level of JCP specific IgE antibody and was not associated with other levels. One explanation may be that allergic disposition influences smoking habits, but the unique condition of nasal mucosa for allergic reaction should be considered.

Antibodies↗
PubMed1994

Identification of adenosine A2 receptor-cAMP system in human aortic endothelial cells.

The involvement of endothelial adenosine A2 receptor-cAMP system in A2 receptor-mediated vasodilation in human aortic endothelial cells (HAEC) was investigated. Reverse transcription-polymerase chain reaction (RT-PCR) revealed the expression of both A2a and A2b receptors mRNA in HAEC. In HAEC, YT-146 (selective A2 receptor-agonist) produced a dose-dependent increase of cAMP production. This increase was inhibited by theophylline. YT-146 also showed a vasodilatory action in isolated rat aorta. The removal of endothelium significantly attenuated this vasodilatory effect. Our results provide the first evidence for the expression of both subtypes of the A2a and A2b receptors which regulate cAMP production in human endothelial cells. The present results also suggest that A2 receptor-cAMP system was involved in the endothelium-dependent vasodilatory actions and may play important roles in regulating vascular functions of HAEC.

Acetylcholine↗
PubMed1994

Quantitation of urinary 1,2,3,4-tetrahydro-beta-carboline and 1-methyl-1,2,3,4-tetrahydro-beta-carboline by high-performance liquid chromatography.

A high-performance liquid chromatographic method was developed to quantify 1,2,3,4-tetrahydro-beta-carboline (TBC) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) in human urine. Urine samples with added internal standard were subjected to a reaction with fluorescamine and solvent extractions to remove the precursor tryptamine, which readily condenses with aldehydes in samples and reagents. Such a pretreatment completely suppressed the artifactual formation of TBC and MTBC during analytical procedures. The purified original tetrahydro-beta-carbolines and the internal standard were separated by reversed-phase ion-pair chromatography with fluorescent detection. Their simultaneous separation was automatically completed in a short time (< 12 min). Both TBC and MTBC were quantified at ng/mL concentrations. The quantitative results revealed a wide variation in urinary levels of TBC and MTBC, possibly indicating that their considerable amounts excreted in the urine originate from dietary sources.

Adolescent↗
PubMed1994

Effects of naftidrofuryl oxalate on microsphere-induced changes in acetylcholine and amino acid content of rat brain regions.

Effects of naftidrofuryl oxalate (naftidrofuryl) on neurotransmitter, acetylcholine, and amino acid content of brain regions following microsphere-induced cerebral embolism were examined to elucidate its possible therapeutic effects on ischemic brain. Rats received 900 microspheres (48 microns in diameter) via the right internal carotid artery, followed by ligation of the right common carotid artery; and histological and biochemical alterations were examined on the 3rd, 5th, and 28th days after embolism. The embolism induced increases in triphenyltetrazolium chloride- (TTC)-unstained areas and decreases in acetylcholine, glutamate, aspartate, and gamma-aminobutyric acid (GABA) contents in the cerebral cortex, striatum, and hippocampus of the right hemisphere, suggesting that microsphere embolism causes severe damage to these brain regions. Hematoxylin-eosin staining of the right cortical sections after embolism showed degeneration and necrosis of nerve cells with chromatolytic nuclei and eosinophilic cytoplasm. Changes in neurotransmitters of the left hemisphere were relatively small. Treatment with naftidrofuryl of the embolized rats with stroke-like symptoms took place from postoperative day 1 to 28. Treatment resulted in a reduction in TTC-unstained areas, less morphological damage to cerebral cortex on the 3rd and 5th days, and an appreciable restoration of acetylcholine content of three brain regions of the right hemisphere throughout the experiment, but restoration of neurotransmitter amino acids was observed to a smaller degree. The results suggest that naftidrofuryl is capable of preventing the development of ischemia-induced, sustained damage to brain regions vulnerable to oxygen deficiency, particularly by improving impaired acetylcholine metabolism.

Acetylcholine↗