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Biomedical subjects

M Munakata

Publications and source records attributed to M Munakata.

At least 127 records · Page 7Linked to original sources
PubMed1994

Clinical characteristics of idiopathic interstitial pneumonia (IIP) with bullae.

Multiple bullae have often been observed in the lungs of patients with idiopathic interstitial pneumonia (IIP). The etiology of bullae has been considered to be distinct from that of interstitial pneumonia and honeycomb lesions seen in IIP. The incidence of bullae was evaluated in 27 IIP patients (male; 23 cases, female; 4 cases) and clinical factors which are related to the development of bulla were analyzed. Of the 27 patients, 16 (59%) had bullae. All 16 were male smokers, and had higher smoking indices (p < 0.01) than patients without bullae. Eleven of the 16 IIP patients with bullae had clubbed fingers (69%, p < 0.05). Roentgenologically, cysts (75%, p < 0.05), low attenuation area (56%, p = 0.06), and honeycomb appearance (94%, p = 0.07) were observed more often in IIP patients with bullae. These results suggest that smoking habits may have a close relationship to the development of bullae seen in patients with IIP.

Aged↗
PubMed1994

A rare case of Young's syndrome in Japan.

A 56-year-old man was admitted for the evaluation of recurrent pulmonary infections. Since the patient presented with the combination of diffuse cystic bronchiectasis, chronic sinusitis and obstructive azoospermia, the diagnosis of Young's syndrome was made. Because the sweat chloride value, pancreatic function and ciliary ultrastructure were normal, this case could be clearly differentiated from cystic fibrosis and primary ciliary dyskinesia. There have been only a few reported cases of Young's syndrome in Japan.

Bronchiectasis↗
PubMed1994

Compliance with long-term dietary salt restriction in hypertensive outpatients.

Eighty hypertensive outpatients were recruited for a dietary salt restriction program to examine long-term compliance. Twenty-four-hour urine samples were collected repeatedly (7.9 +/- 2.6 times, mean +/- s.d.) during a follow-up period of 6.4 +/- 1.7 years. After initial urine collection, nutritional education was carried out by dietitians to reduce dietary salt intake to 8 g/day or less. After every urine collection, the subjects were given advice by doctors on salt restriction, if necessary. The mean 24-hour urinary salt excretion (U-NaCl) and the mean urinary salt/creatinine ratio (U-NaCl/U-Cr) varied considerably both among and within individuals. U-NaCl/U-Cr, but not U-NaCl, in females was significantly higher than that in males, and in middle-aged subjects than in young subjects. U-NaCl and U-NaCl/U-Cr tended to decrease in the summer. In spite of the repeated educational effort, neither U-NaCl nor U-NaCl/U-Cr was different in the first control samples from that in the last samples. When 57 subjects were divided into three groups according to the urinary salt excretion level, U-NaCl was consistently higher during a follow-up period in the high-salt excretion group than in the mid-salt excretion group, while U-NaCl in the low-salt excretion group was initially lower than, but finally similar to, that in the mid-salt excretion group. These results suggest that: (1) multiple 24-hour urine samplings are required to assess urinary salt excretion in individuals; (2) the influence of age and sex should be taken into account in interpreting U-NaCl/U-Cr; and (3) it seems difficult to achieve long-term dietary salt restriction as a non-pharmacologic treatment of hypertension in an outpatient clinic.

Adult↗
PubMed1994

[Present status of idiopathic interstitial pneumonia--from epidemiology to etiology].

The present status of idiopathic interstitial pneumonia (IIP) was evaluated from data collected as part of the Financial Support Program for patients with IIP, conducted in Hokkaido since 1979. The prevalence of IIP in 1992 was 4.08/100,000, and the yearly incidence was 1.23/100,000. The ratio of men to women was 1.85/1.0. Under age 55, women were more numerous than men, and over age 55, men were more numerous than women. Clinical and epidemiological analyses of the patients with IIP, with collagen vascular disease-interstitial pneumonia suggested possible contribution of dust inhalation to the etiology IIP. A prospective study revealed that about 20% of the subjects had systemic signs and symptoms of collagen diseases from 2 months to 10 years after the diagnosis of IIP. In addition, about 15% of the subjects with IIP developed lung cancer during the follow-up period. This incidence was significantly higher than that in the patients with chronic obstructive pulmonary diseases and the same smoking history, which suggests that IIP itself is a risk factor for lung cancer.

Aged↗
PubMed1994

[A case of bronchiectasis accompanied by ulcerative colitis (UC) and HTLV-1 associated myelopathy (HAM)].

We report a case of bronchiectasis with marked thickening of the respiratory tract wall occurring in a 37-year-old man with UC and HAM. He was diagnosed as UC at age 20. HTLV-1 was presumably transmitted to this patient by means of a blood transfusion he received at around age 30. On admission, chest X-ray films, tomography and CT-scan revealed dilated lumens and thickened airway walls extending from the trachea to subsegmental bronchi. Pulmonary function tests showed hypoxemia and mixed ventilatory disturbance with a predominantly obstructive component. HAM was diagnosed on the basis of neurological examination and cerebrospinal fluid analysis. A biopsy specimen from the carinal mucosa showed marked T cell infiltration. In these T cells, we detected polyclonal integration of HTLV-1 proviral DNA. Some of the infiltrating T cells showed atypia. In recent times, respiratory diseases other than infiltration of adult T-cell leukemia cells or opportunistic infection have been reported in HTLV-1 carriers and new clinical entities designated as HABA (HTLV-1 associated bronchiolo-alveolar disorder) and HBA (HTLV-1 associated bronchopneumopathy) have been proposed. This case is classified among these new entities, in a broad sense, and is a rare case in that the respiratory disorder is apparently related to UC.

Adult↗
PubMed1994

Pressor effect of recombinant human erythropoietin: results of home blood pressure measurements in hemodialysis patients.

We investigated whether the treatment of anemic hemodialysis patients with a low dose of recombinant human erythropoietin (rHEpo) for a short period would increase the blood pressure (BP). Home BP measurements were used to detect minute increases in BP. Fifty-one anemic patients on maintenance hemodialysis with a hematocrit of 25% or less received rHEpo at the dose of 4500 IU/week by the intravenous route for 8 weeks. Overall, rHEpo did not increase the BP whether measured at home or in the clinic (causal BP). Hemoglobin concentration increased significantly from 7.1 +/- 0.7 to 8.8 +/- 0.7 g/dl. Patients were classified into two groups according to the change in mean (M) home BP induced by rHEpo: a pressor group (delta MBP > or = 5 mmHg, n = 17) and a non-pressor group (delta MBP < 5 mmHg, n = 34). The hemoglobin concentration rose significantly in both groups, but there was no change in casual BP. Home blood pressure measurements showed a gradual and continuous rise in BP in the pressor group, but not in the non-pressor group. Patients administered antihypertensive medications before rHEpo treatment accounted for 88% of the former and 50% of the latter groups. Two patients with malignant nephrosclerosis were included in the pressor group. The findings indicate that rHEpo, even given at a low dose for a short period, elevates the BP, as determined by home BP measurement, but not by casual measurements obtained in the clinic.

Adult↗
PubMed1993

Nystatin-perforated patch recordings disclose KA-operated outward currents in rat cortical neurons.

Kainate (KA)-induced responses were studied in acutely dissociated rat cortical neurons. KA elicited the inward currents with conventional whole-cell and nystatin-perforated patch recordings under voltage-clamp condition. An additional outward current was observed only with the perforated patch recording. The outward current was due to the activation of K+ current by Ca2+ passing through the KA channels. This K+ channel was sensitive to both iberiotoxin and tetraethylammonium (TEA)-Cl. This K+ channel may serve to limit the depolarization during excessive KA-mediated excitation.

Animals↗
PubMed1993

Heterogeneous distribution and developmental change of metabotropic glutamate receptors in rat hippocampal CA1 pyramidal neurons.

The metabotropic glutamate (mGlu) response in dissociated rat hippocampal CA1 pyramidal neurons was recorded, using the nystatin-perforated patch-clamp technique. The mGlu response was localized in the ventral site of the hippocampal CA1 region. In both the ventral and dorsal sites of the CA1 region, the current amplitude of the mGlu responses as well as their induction probability (responsiveness) were reduced with development of the brain.

Animals↗
PubMed1993

Caffeine response in pyramidal neurons freshly dissociated from rat hippocampus.

The effect of caffeine on the CA1 pyramidal neurons freshly dissociated from rat hippocampus was investigated with nystatin-perforated patch technique under voltage-clamp condition. Caffeine evoked a transient outward current (Icaffeine) in a concentration-dependent manner at a holding potential of -40 mV. The activation and inactivation of Icaffeine were accelerated with increasing caffeine concentration. The reversal potential for Icaffeine was close to K+ equilibrium potential. The Icaffeine was not blocked by apamin and 4-aminopyridine but suppressed by charybdotoxin, tetraethylammonium, quinine and Ba2+. Thus, the pharmacological characteristics of Icaffeine were similar to those of Ca(2+)-activated K+ current having a large conductance (IC), which generates a fast afterhyperpolarization (a.h.p.). Icaffeine was depressed by pretreatment with a membrane-permeant Ca2+ chelator (BAPTA-AM) and by depletion of the Ca(2+)-induced Ca2+ release (CICR) pool with ryanodine. A blocker of CICR sites, procaine, potently depressed the Icaffeine. In the absence of the extracellular Ca2+, an application of 10 mM caffeine depleted the caffeine-sensitive Ca2+ pools. Icaffeine recovered in an exponential fashion in the presence of the extracellular Ca2+. It was concluded that rat hippocampal pyramidal neurons have a caffeine-sensitive Ca2+ pool. Furthermore, the Ca2+ released from the pool evokes K+ current similar to IC current and hyperpolarizes the neurons.

4-Aminopyridine↗
PubMed1993

Effects of cicletanine on the urinary excretion of prostanoids and kallikrein, and on renal function in man.

The effects of cicletanine, a new antihypertensive agent, on the prostaglandin-kallikrein system and the renin-angiotensin system were studied. A single oral dose of 200 mg cicletanine or placebo was administered to 9 healthy male volunteers, with samples of blood and urine obtained before and 2 hours after drug administration. Cicletanine increased the urine flow, urinary excretion of sodium, and fractional excretion of sodium by 47%, 115%, and 104%, respectively. While the excretion of 6-keto-prostaglandin-F1 alpha was enhanced significantly, urinary excretion of thromboxane-B2, prostaglandin-E2, and kallikrein were unchanged. Cicletanine also did not alter plasma renin activity, plasma aldosterone concentration, or creatinine clearance. These observations suggest that cicletanine may suppress sodium reabsorption at the nephron, and it may stimulate prostacyclin generation with no effect on that of thromboxane-A2. Thus cicletanine may be beneficial in the management of cardiovascular disorders in which the equilibrium between prostacyclin and thromboxane is disturbed.

Administration, Oral↗
PubMed1993

Rhythmic oscillations of blood pressure and R-R interval in patients with chronic renal failure.

Rhythmic blood pressure (BP) and R-R interval (R-R) oscillations at low-, mid- and high-frequency bands (LF: 0.02-0.06 Hz; MF: 0.07-0.14 Hz; HF: 0.15-0.40 Hz) were compared between uraemic patients maintained on haemodialysis and control subjects. The LF and MF power spectra of BP were attenuated more in patients than in controls. With subjects standing, the MF power spectrum of BP increased significantly in both groups. With subjects supine, the plasma norepinephrine concentration was higher, and its increment upon standing was greater in patients than in controls. Each R-R frequency power spectrum decreased more in patients than in control subjects. The HF power spectrum of R-R, i.e. a vagal tone index, systematically decreased upon standing in the control subjects but not in the patients. The linear coupling between BP and R-R oscillations was strongest in the HF band, decreasing in the MF and LF bands. Transfer function analysis indicated that, in uraemic patients, linear BP/R-R relationships were altered in the HF band but remained normal in the LF and MF bands. The present results suggest that, first, the decreased amplitude of Mayer waves, i.e. the MF power spectrum of BP, observed in uraemic patients can be attributed to low sensitivity of the vasculature to sympathetic stimuli, and, secondly, autonomic modulation of linear BP/R-R relationships is frequency-dependent.

Adult↗
PubMed1993

Spontaneous synaptic transmission in dissociated Meynert neurons with the attached synaptic boutons.

1. Neurons acutely dissociated from the nucleus basalis of Meynert of adult rats showed spontaneous currents with rapid onset and slow decay under the whole-cell patch-clamp recording. 2. The current had the reversal potential close to the theoretical Cl- equilibrium potential (ECl) and was suppressed by 2 x 10(-6) M bicuculline and 3 x 10(-6) M strychnine. 3. The spontaneous current was suppressed reversibly in the Ca(2+)-free solution containing either EGTA or BAPTA (5 mM). The enhancement of the frequency and amplitude of the current was observed with elevated extracellular K+ concentration, which was also suppressed in the presence of the Ca(2+)-free solution. 4. Nicardipine, a blocker of voltage-dependent Ca2+ channels, had an inhibitory effect as well. 5. A selective GABAB agonist, baclofen, blocked the spontaneous current, whereas a selective antagonist, phaclofen, potently enhanced the current. 6. It is concluded that the observed spontaneous current was a spontaneous inhibitory postsynaptic current (IPSC) due to the release of GABA from the attached synaptic boutons. The release was suppressed by a GABAB receptor activation, indicating that the GABAB receptor regulates the release of GABA from nerve terminals and acts as a negative autoreceptor.

Animals↗
PubMed1993

Age-specific characteristics of nocturnal blood pressure in a general population in a community of northern Japan.

The age- and gender-specific profile of circadian blood pressure variation was examined by monitoring ambulatory blood pressure (ABP) in 477 untreated subjects in a rural community of northern Japan. Autoregressive spectral analysis demonstrated three major peaks at around 24, 12, and 8 h. We fitted a truncated Fourier series with three harmonics to the blood pressure (BP) data using least squares regression. More than half of the BP and pulse rate periodic curves were bimodal, one-third were trimodal, and the remainder were unimodal. The nadir of BP appeared between 00:00 and 01:30, and that of pulse rate occurred between 00:30 and 02:00. The nadir of systolic and diastolic BP, as well as pulse rate, appeared earlier with increasing age, and the difference between subjects in their 20s and those in their 70s was about 1 h. The amplitude of 24 h BP decreased with increasing age in men, but not in women. This type of information on the circadian BP profile of a general population is useful for the diagnosis and treatment of hypertension.

Adult↗
PubMed1993

Characteristics of a community-based distribution of home blood pressure in Ohasama in northern Japan.

OBJECTIVE: To evaluate the distribution, reference values and day-to-day variation of blood pressure of untreated subjects measured at home. DESIGN: Cross-sectional study of a cohort. SETTING: General community in northern Japan. SUBJECTS: Blood pressure was measured in 871 subjects (mean +/- SD age 46.0 +/- 19.5 years, range 7-98, constituting 38.7% of the local population of Uchikawama region, Ohasama) who were not receiving antihypertensive medication. METHODS: Subjects measured their own blood pressure at home at least three times (mean +/- SD 19.7 +/- 8.4) each morning using a semi-automatic oscillometric blood pressure measuring device. Screening blood pressure was measured once. MAIN OUTCOME MEASURES: Distribution of home blood pressure in the study population as a whole and with respect to age and sex, and the distribution of day-to-day variation of home blood pressure were determined. RESULTS: Mean home blood pressure was 117.3 +/- 13.4/69.3 +/- 9.7 mmHg (95% confidence interval 116.4-118.2/68.7-70.0). The 95th centile value was 143/85 mmHg, mean+SD 131/79 mmHg and mean + 2SD 144/89 mmHg. Mean screening blood pressure was 126.2 +/- 18.9/72.1 +/- 11.7 mmHg (95th centile 159/92 mmHg). Age- and sex-specific 95th centile values as well as mean +/- SD were obtained. Mean+SD, mean + 2SD and the 95th centile values obtained as reference upper limits of home blood pressure from subjects identified as normotensive by screening blood pressure (n = 707) were 125/77, 137/86 and 134/83 mmHg, respectively. Home blood pressure increased gradually with increasing age in both men and women, although blood pressure was significantly higher in men until 50 years of age. Day-to-day variation of home systolic blood pressure also increased with age. CONCLUSION: Since the distribution of home blood pressure values was affected by age and sex, age- and sex-matched reference values for home blood pressure should be established. Home blood pressure values in elderly subjects should be evaluated carefully, since these exhibit greater day-to-day variation.

Adolescent↗
PubMed1993

Differential properties of type I and type II benzodiazepine receptors in mammalian CNS neurones.

1. The effects of benzodiazepine receptor (BZR) partial agonists, Y-23684 and CL218,872, were compared with its full agonist, diazepam, on gamma-aminobutyric acid (GABA)-induced Cl- current (ICl) in acutely dissociated rat cerebral cortex (CTX), cerebellar Purkinje (CPJ) and spinal ventral horn (SVH) neurones, by the whole-cell mode patch-clamp technique. 2. The GABA-induced responses were essentially the same in both SVH and CPJ neurones, but the KD value of the GABA response in CTX neurone was lower than those in the other two brain regions. 3. Enhancement of the GABA response by the two partial agonists was about one-third of that by diazepam in the SVH neurones (where type II subtype of BZR, BZ2, is predominant), whereas these partial agonists potentiated the GABA response as much as diazepam in CPJ neurones (where the type I subtype of BZR, BZ1, is predominant). In CTX neurones where both type I and II variants are expressed, the augmentation ratio of the GABA response by diazepam was between the values in CPJ and SVH neurones. 4. In concentration-response relationships of BZR partial agonists, the threshold concentrations, KD values and maximal augmentation ratio of the GABA response were similar in all CTX, CPJ and SVH neurones. Also, in all preparations, the threshold concentration and KD values of diazepam action were 10 fold less than those induced by partial agonists. 5. All BZR agonists shifted the concentration-response relationship for GABA to the left without changing the maximum current amplitude, indicating that activation of both BZ1 and BZ2 increase the affinity of the GABAA receptor for GABA. 6. The results are important in clarifying the mechanism of anxiety and might explain the anxioselectivity of BZR partial agonists.

Aging↗