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Biomedical subjects

A Masuda

Publications and source records attributed to A Masuda.

At least 163 records · Page 9Linked to original sources
PubMed1994

Argyrophilic nucleolar organizer regions as a prognostic indicator of laryngeal carcinomas.

Nucleolar organizer regions (NORs) were studied in surgically removed specimens from 76 patients with squamous cell carcinomas of the larynx using an argyrophilic (Ag) staining technique. The mean number of AgNORs per nucleus was 4.3 +/- 1.38 (SD). The mean AgNOR number for T1 or T2 disease was statistically lower than that for T3 or T4 lesions (P < 0.05). The mean AgNOR number was lower in patients with N0 disease than in patients with N1 or N2 or N3 tumors (P < 0.05). There was also a statistically significant difference between the mean AgNOR number for stage II and stage III disease (P < 0.01), for stage III and stage IV disease (P < 0.05), but not for stage I and stage II disease. According to the histological grading, there was a significant difference between the mean AgNOR number for the well-differentiated and moderately differentiated tumors (P < 0.05), and for the moderately differentiated and poorly differentiated types (P < 0.01). These results suggest that the number of AgNORs in the nucleus is a significant indicator of laryngeal carcinomas.

Adult↗
PubMed1994

Preliminary findings of chromosomal alterations and expression of cell cycle genes in head an neck tumors.

The genesis and progression of malignant tumors may be related to certain somatic mutations and the accumulation of multiple chromosomal alterations. Using four freshly resected malignant tumors, we investigated the relationship between chromosomal alteration and expression of cell cycle regulatory genes. Specimens of thyroid hyperplasia and normal thyroid tissue were also investigated. As cell cycle regulating genes, we chose the cdc2 gene that encodes the p34cdc2 protein kinase, a major kinase of the cell cycle, and the RCC1 gene that is essential for coupling between S and M phases. Three of the malignant tumors contained cells with chromosomal alterations, including one polyploid and two aneuploid. The DNA content of cells in thyroid hyperplasia was the same as in the normal gland. The amount of p34cdc2 protein was very low in cells of both normal thyroid and hyperplastic tissue, and grew very slowly as compared with malignant tumors. There was no significant relationship between the amount of RCC1 and ploidy pattern.

Adaptor Proteins, Signal Transducing↗
PubMed1994

Cutaneous iontophoretic application of condensed lidocaine.

The purpose of this study was to determine whether iontophoretic application of high concentrations of lidocaine, with the same current, would produce cutaneous local anaesthesia rapidly enough for clinical practice. Twenty healthy volunteers, 17 male and three female, were selected for study. After five-minute or ten-minute iontophoresis using lidocaine 4, 10, 20, 30, 50%, we assessed the response to pin prick with a 27-gauge sterile needle inserted to the depth of 2 mm at five random locations in the iontophoretically-stimulated area. Also, plasma lidocaine concentrations were measured in the venous blood samples which had been taken from three male subjects, at 3, 10, and 30 min after iontophoresis with lidocaine 50%. The pain score after five-minute iontophoresis was higher than that after ten-minute iontophoresis, using each concentration of lidocaine (P < 0.001), whereas the pain scores had no correlation with lidocaine concentration within five-minute and ten-minute iontophoresis groups, respectively (P: NS). On the other hand, plasma lidocaine concentration was < 1.0 micrograms.ml-1 in all samples. No side effects other than erythema were observed after iontophoresis using high concentrations of lidocaine up to 50%. These results showed that by increasing the lidocaine concentration of the applied solution up to 50%, the application time of iontophoresis cannot be reduced from ten to five minutes without losing analgesic effect, although iontophoresis itself can be performed with safety.

Administration, Cutaneous↗
PubMed1994

Serum of Boophilus microplus infested cattle reacts with different tick tissues.

Five cattle were each experimentally infested with 30,000 Boophilus microplus larvae and their humoral immune response to salivary gland, gut, embryo and larval extracts during infestation were determined by enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Serum antibodies to embryo extract were detected by ELISA 21 days after infestation and antibodies to the other extracts 28 days following infestation. Using Western blot analysis, new bands were recognized and others disappeared during infestation. One low molecular weight band (10,000) was detected in embryo extract 14 days after infestation and in other extracts 28 days after infestation; another band (12,000 mol. wt.) in embryo, larval and salivary gland extracts was detected at the same time as the 10,000 mol. wt. band. These results suggest that common antigens are present in different tissues of B. microplus.

Animals↗
PubMed1994

Morphometrical analysis of cystadenolymphoma (Warthin's tumor). Subclassification and characterization of the lymphoid stroma in comparison with gastric lymphoid follicles.

Morphometrical analysis was applied to cystadenolymphoma (Warthin's tumor, adenolymphoma: CAL). By quantitative analysis of tissue sections, the examined cases were divided into three subtypes according to the ratio of the lymphoid stroma (LS) to the whole tissue: type I "stroma-rich type", the LS of this type was more than 57% of the whole tissue; type II "typical type", the LS of this type was 37% to 56% of the whole tissue; and type III "stroma-poor type", the LS of this type was less than 36% of the whole tissue. The average age of the patients in subtypes I, II and III was 57.7, 68.0, and 62.4 years, respectively. The age of the patients with type I CAL was significantly lower than that of those with type II CAL. In many type II cases, a reticular distribution of IgE in the germinal centers was frequently observed. From an analysis of the sections immunohistochemically stained with monoclonal antibodies to B and T cells, there appeared to be a trend that the greater the percentage of the LS to the whole tissue, the lower the ratio of B cell region to the LS. In contrast to CAL, an analysis of the change of the ratio of B cell region to the lymphoid follicles (LF) seen in the gastric mucosa of patients with chronic gastritis showed that the larger the volume of LF, the higher the ratio of the B cell region to the entire LF.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenolymphoma↗
PubMed1994

Effect of tetanic stimulation on subsequent train-of-four responses at various levels of vecuronium-induced neuromuscular block.

Tetanic stimulation influences subsequent neuromuscular responses. In addition, the tetanus-induced changes in neuromuscular responses differ according to the level of neuromuscular block at which tetanic stimulation is delivered. We studied the tetanus-induced effect on subsequent train-of-four (TOF) responses at various levels of vecuronium-induced neuromuscular block in 45 anaesthetized patients. Tetanic stimulation was applied when a twitch height of T1 returned to 25%, 50% and 75% of its control twitch height (T0) (groups 1, 2 and 3, respectively) after administration of vecuronium 0.1 mg kg-1. Maximum post-tetanic percentage increases in TOF responses in groups 1, 2 and 3 were 257 (SD 119)%, 107 (75)% and 68 (54)% for T1/T0 (P < 0.001 for group 1 vs 2; P < 0.001 for group 1 vs 3) and 535 (259)%, 421 (213)% and 292 (171)% for T4/T1 (P < 0.01 for group 1 vs 3), respectively. Durations of post-tetanic increases in TOF responses in groups 1, 2, and 3 were 52 (19) s, 37 (14) s and 32 (13) s for T1/T0 (P < 0.05 for group 1 vs 2; P < 0.01 for group 1 vs 3) and 53 (17) s, 46 (15) s and 35 (12) s for T4/T1 (P < 0.05 for group 1 vs 3), respectively. These data suggest that the tetanus-induced effect on subsequent TOF is more apparent and lasts longer at greater degrees than at lesser degrees of neuromuscular block.

Adult↗
PubMed1994

Testosterone treatment enhances thromboxane A2 mimetic induced coronary artery vasoconstriction in guinea pigs.

Thromboxane A2 (TXA2) has been implicated as an important mediator of cardiovascular diseases. There have been several clinical reports of acute myocardial infarctions occurring in young male athletes abusing anabolic steroids. The effects of treatment of male Guinea pigs with testosterone on the responses to U46619, a TXA2 receptor agonist, in the isolated perfused heart were determined. The maximum pressor responses of the isolated perfused Guinea pig heart to U46619 were significantly (P < 0.05) greater in the Guinea pigs treated with testosterone compared to the controls. These results indicate that testosterone can enhance coronary artery vascular reactivity to TXA2.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1994

Auditory brainstem response (ABR) peak amplitude variability reflects individual differences in cochlear response times.

Previously, it was shown [Don et al., J. Acoust. Soc. Am. 94, 2135-2148 (1993)] that cochlear response times are gender specific and about 13% shorter in females than in males. It is also suggested that one of the possible reasons click-evoked auditory brainstem response (ABR) waveforms recorded from females are better defined and have larger amplitudes than those of males is due to a sex difference in cochlear response times leading to better synchronization of the cochlear output across the frequency regions. Variability in cochlear response times would also lead to variability in click evoked ABR amplitudes. The high-pass noise masking derived ABR technique was used to investigate the effect of normalizing the individual temporal variability at the neural and cochlear levels. This involved adjusting for differences in neural conduction time (I-V delay) by a compression or expansion of the derived ABR waveforms and by adjusting for differences in cochlear response times by a shift of the derived ABR waveforms. A summation of the compressed and shifted ABRs results in a normalized unmasked ABR waveform that can then be compared for amplitude variability with the unprocessed unmasked ABRs. Compensation for the neutral I-V variability had little effect while compensation for cochlear response times, particularly the delay between the 5.7- and 2.8-kHz regions, greatly affected the amplitude of wave V of the compounded ABR. This work provides a better understanding of the significant relationship between cochlear response times and variability of the ABR peak amplitudes.

Adolescent↗
PubMed1994

Insulin sensitivity and the effects of insulin on renal sodium handling and pressor systems in essential hypertensive patients.

Insulin resistance and hyperinsulinemia are linked with essential hypertension. To clarify insulin sensitivity in Japanese essential hypertensive patients and the role of insulin resistance in these patients, a euglycemic hyperinsulinemic glucose clamp was applied in 17 essential hypertensive patients and 12 normotensive subjects. The mean glucose infusion rate was used as an indicator of insulin sensitivity (M value). This study revealed a significantly lower M value in essential hypertensive patients than in normotensive subjects. Increased plasma norepinephrine, renin activity, and aldosterone levels were observed after hyperinsulinemia for 120 minutes after glucose clamp in normotensive subjects and essential hypertensive patients. Urinary sodium excretion and fractional excretion of sodium were decreased in essential hypertensive patients as well as normotensive subjects during glucose clamp compared with the period before glucose clamp. No difference in the percent change was observed between essential hypertensive patients and normotensive subjects. These results indicate that selective insulin resistance with respect to glucose metabolism exists in essential hypertensive patients and that insulin action on renal sodium handling and pressor systems was maintained in these patients.

Aldosterone↗
PubMed1994

Does insulin resistance participate in an impaired glucose tolerance in primary aldosteronism?

It has been reported that glucose intolerance is occasionally found in primary aldosteronism. In this study, we measured insulin sensitivity by the euglycaemic hyperinsulinaemic glucose clamp technique and ability to release insulin by 75 g oral glucose tolerance test (OGTT) in primary aldosteronism. Seven patients with primary aldosteronism (PA) (53.7 +/- 3.4 years; mean +/- SEM) and eight normotensive subjects (NS) (57.5 +/- 2.6 years) were employed in this study. The two-hour euglycemic hyperinsulinaemic glucose clamp technique was performed in seven PA before adrenalectomy, six PA after adrenalectomy and eight NS. The 75 g OGTT was also done in five PA before and after adrenalectomy and eight NS. The mean rate of glucose infusion to maintain euglycemia for the last 30 minutes of the clamp technique was used as an indicator of insulin sensitivity (M-value). The total blood glucose levels during 75 g OGTT (area under the curves) (sigma blood glucose) were significantly higher in PA than those in NS, and the total insulin levels during 75 g OGTT (area under the curves) (sigma IRI) were significantly lower in PA than those in NS. After adrenalectomy in PA, blood glucose levels were significantly decreased and IRI were significantly increased compared with the normal range. There was a significant positive correlation (P < 0.05, r = 0.71) between serum potassium levels and IRI in PA which were determined before and after adrenalectomy. In PA, M-values (240.7 +/- 14.6 mg/m2/min) were significantly higher than those in NS (199.0 +/- 12.3 mg/m2/min).(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1994

[Osteoporosis after menopause and oophorectomy].

Characteristics of osteoporosis occurring after menopause and oophorectomy are described. Changes in hormone dynamics induced by menopause or oophorectomy lead to high metabolic turnover of bone, characterized by increased bone formation and resorption. The increase in bone resorption surpasses that of bone formation, resulting in decreased bone mineral density (BMD). Even before the onset of menopause, a transient decrease in estrogen concentrations can produce decreases in BMD that are comparable to those occurring after menopause or oophorectomy. Long-term observation of women undergoing premature menopause indicates that BMD progressively continues to decline in association with high bone metabolic turnover. There was no significant difference between BMD, 3 years after menopause, compared with that 3 years after oophorectomy, a time when the effect on BMD are fully evident. These findings indicate that osteoporosis, associated with either menopause or oophorectomy, can be managed in the same manner in a clinical setting.

Biomarkers↗
PubMed1994

The Gordon Wilson Lecture. Regulation of thromboxane A2 receptors by testosterone: implications for steroid abuse and cardiovascular disease.

Thromboxane A2 (TXA2), a platelet aggregator and vasoconstrictor, has been implicated as a potential pathophysiologic mediator of a wide variety of cardiovascular diseases. It is well established that men are at greater risk for cardiovascular disease compared to premenopausal females. Abuse of androgenic/anabolic steroids has been associated with thrombotic cardiovascular diseases in young male athletes. These observations along with several others have led to the hypothesis that testosterone may regulate the expression of TXA2 receptors. Rat aortic smooth muscle cells (RASMC) and human erythroleukemia cells (HEL), a megakaryocyte-like cell, were incubated with testosterone. TXA2 receptor affinity (Kd) and density (Bmax) were determined via equilibrium binding experiments using the radiolabeled TXA2 mimetic [125I]-BOP. Testosterone significantly increased the Bmax without any significant change in Kd. Hydroxyflutamide (1 microM), an androgen receptor antagonist, completely blocked the effect of testosterone. Dihydrotestosterone, the active metabolite of testosterone also increased Bmax in a concentration-dependent manner and was more potent than testosterone. These observations along with several others are consistent with the notion that androgenic steroids may regulate the expression of functional TXA2 receptors in HEL and RASMC. These results raise the possibility that the increase in TXA2 receptor density induced by testosterone may contribute to its thrombotic potential in cardiovascular diseases.

Animals↗
PubMed1994

[Flumazenil antagonism of midazolam-induced respiratory depression].

Flumazenil, a benzodiazepine antagonist, reliably reverses midazolam-induced sedation, but its effect on respiratory depression has not been clarified completely. Ten healthy male volunteers received midazolam 0.1 mg.kg-1. Then they received flumazenil 0.5 mg (n = 9) and 1.0 mg (n = 1), intravenously. Rib-cage (RC) and abdominal wall (ABD) movement was measured by mercury-in-silastic strain gauge. Nasal air flow (FLOW), genioglossal electromyogram (EMG) and oxygen saturation (SaO2) were recorded simultaneously. Midazolam caused significant increases of RC movement and respiratory rate, and decreases of ABD movement, FLOW, EMG and SaO2. After administration of flumazenil, although respiratory rate returned to the pre-midazolam values, RC movement decreased on the contrary. ABD movement, FLOW, EMG, SaO2 did not recover to the pre-midazolam values. These data suggest that flumazenil 0.5 mg reverses midazolam-induced sedation completely, but is partially effective for some parameters related to respiratory depression.

Adult↗
PubMed1994

[Statistic studies on bacteria isolated from urinary tract infections (report 6: isolation rate and drug sensitivity from 1988 through 1989)].

We examined the bacteria isolated from urine of patients in our department from 1988 though 1989. A total of 809 strains were isolated from the outpatients. They were 241 strains of gram-positive bacteria (29.8%). E. coli (32.0%) was isolated most frequently, followed by Enterococcus spp. (9.9%), Proteus group (7.4%), S. epidermidis (6.2%), P. aeruginosa (5.1%) and others. A total of 412 strains were isolated from the inpatients. They consisted of 173 strains of gram-positive bacteria (42.0%). Enterococcus spp. (17.0%) was isolated most frequently, followed by P. aeruginosa (12.6%), S. epidermidis (9.7%), E. coli (7.3%), S. aureus (6.6%) and others. Fewer P. aeruginosa, S. marcescens and Proteus group were isolated from the outpatients and fewer S. marcescens, E. coli and K. pneumoniae from inpatients than previously. More S. aureus were isolated abruptly from the inpatients and more E. coli were isolated from the outpatients than previously. E. cloacae, S. epidermidis, S. aureus and Corynebacterium spp. all isolated from inpatients showed lower antimicrobial sensitivity than those isolated from the outpatients.

Bacteria↗
PubMed1994

Follicular dendritic cell function and murine AIDS.

Infection of mice with LP-BM5 elicits an immunodeficiency state referred to as murine acquired immune deficiency syndrome (MAIDS). Shortly after infection, retrovirus particles become associated with follicular dendritic cells (FDC) and this study was undertaken to determine whether retroviruses alter FDC functions. The FDC functions examined included the ability to: (1) retain antigen (Ag) trapped prior to infection; (2) trap new Ag after infection; (3) maintain specific IgG responses; and (4) provide co-stimulatory signals to B cells. Mice were infected with LP-BM5 and the ability of their FDC to trap and retain 125I-Ag (HSA) was assessed. Serum anti-HSA levels were monitored and FDC co-stimulatory activity was indicated by increased B-cell proliferation. HSA trapped on FDC prior to infection began to disappear by 3 weeks and was practically gone by 6 weeks. Serum anti-HSA titres were maintained normally for about 3 weeks after infection and then declined precipitously. The ability of FDC to trap new Ag began to disappear around the second and third week of infection and was markedly depressed by the fourth week. However, FDC recovered from infected mice retained their ability to co-stimulate anti-mu- and interleukin-4 (IL-4)-activated B cells throughout a 5-week period. In short, the ability of FDC to trap and retain specific Ag and maintain specific antibody levels was markedly depressed after retrovirus infection. However, FDC from infected mice continued to provide co-stimulatory signals and these signals may contribute to the lymphadenopathy and splenomegaly characteristic of MAIDS.

Animals↗
PubMed1994

[Basic and clinical evaluation of the effect of pirarubicin against head and neck cancer--chemosensitivity test and a comparative study with doxorubicin].

The chemosensitivities of 77 samples of human head and neck cancer were examined by in vitro succinate dehydrogenase inhibition (SDI) test. The tumor tissues obtained at biopsy specimens were exposed to doxorubicin (DXR) and pirarubicin (THP). The average decrease of the enzyme activity by THP was significantly greater than that by DXR. In 60 cases of squamous cell carcinomas, the chemosensitivity of poorly differentiated type tended to be higher compared to the well differentiated type. It is suggested from there results that THP is a more effective anticancer drug than DXR against human head and neck cancers. Clinically good responses were obtained in a systemic chemotherapy of such as head and neck adenoid cystic carcinomas by combining THP with other anticancer drugs such as CDDP (or CBDCA) and CPA.

Adult↗