Search PubMed⌕ Search

Biomedical subjects

K Tsunoda

Publications and source records attributed to K Tsunoda.

At least 73 records · Page 4Linked to original sources
PubMed1996

20-HETE requires increased vascular tone to constrict rabbit afferent arterioles.

Renal production of 20-hydroxyeicosatetraenoic acid (20-HETE), a cytochrome P-450-dependent arachidonate metabolite, increases during development of hypertension in spontaneously hypertensive rats, and inhibition of its production prevents hypertension. Since 20-HETE is a potent vasoconstrictor, these findings suggest that 20-HETE may contribute to the development of hypertension by elevating renal vascular resistance. In this study we examined the direct action of 20-HETE on the afferent arteriole, a vascular segment crucial to the control of renal vascular resistance. Rabbit afferent arterioles were microperfused at 60 mm Hg in vitro, and 20-HETE was added to the lumen. Although 20-HETE (10(-10) to 10(-6) mol/L) had no effect on the diameter of non-treated afferent arterioles (n=6), it caused dose-dependent constriction when vascular tone was increased with norepinephrine (0.3 micromol/L); 20-HETE at 10(-6) mol/L decreased diameter by 43 +/- 4% (n=6, P < .001). This constriction was abolished by disrupting the endothelium (n=5). Moreover, pretreatment with the cyclooxygenase inhibitor indomethacin (50 micromol/L) or the thromboxane/endoperoxide receptor antagonist SQ29548 (1 micromol/L) significantly (P < .03) attenuated 20-HETE-induced constriction: 20-HETE at 10(-6) mol/L constricted norepinephrine-treated afferent arterioles by 28 +/- 3% (n=6) and 25 +/- 4% (n=5), respectively. These results demonstrate that an increase in afferent arteriolar tone is required for the vasoconstrictor action of 20-HETE, which is partly mediated by the endothelial cyclooxygenase pathway. THus, increased production of 20-HETE in the kidney and increase in afferent arteriolar tone, both of which often precede the development of hypertension, may synergistically contribute to the development of hypertension by elevating renal vascular resistance.

Animals↗
PubMed1996

Bilateral aldosterone-producing adenomas in two patients diagnosed by immunohistochemical analysis of steroidogenic enzymes.

Bilateral adrenal aldosterone-producing adenomas (APA) are rare. It is important to distinguish bilateral APA from idiopathic hyperaldosteronism (IHA) which is due to bilateral hyperplasia of the adrenal cortex. We present two patients with bilateral APA in whom the diagnosis was made histochemically by analyzing steroidogenic enzymes. They showed hypokalemia, high plasma aldosterone concentration (PAC) and suppressed plasma renin activity (PRA). Bilateral adrenal tumors were represented by computed tomography, and surgical resection was performed. In both cases, cytochrome P-450 and other enzymes that were involved in aldosterone synthesis were found mainly in tumor, but little in the zona glomerulosa of the adjacent adrenals, which showed paradoxical hyperplasia. Such cases are difficult to distinguish from IHA. The two disorders were differentiated by immunohistochemical analysis of steroidogenic enzymes.

3-Hydroxysteroid Dehydrogenases↗
PubMed1996

[Epidural buprenorphine does not improve diaphragmatic function after upper abdominal surgery].

We investigated the effect of epidural buprenorphine on diaphragmatic function using respiratory inductive plethysmography (RIP) in seven healthy patients after upper abdominal surgery. After surgery, changes of rib cage contribution to tidal volume (%RC) increased significantly from 25.3 +/- 7.3 (mean +/- SD) to 50.7 +/- 14.8% (P < 0.05). After the injection of epidural buprenorphine, visual analogue scale (VAS) score decreased significantly from 8.3 to 3.3 (P < 0.05). But, %RC was unchanged compared to the value before the injection. These results indicate that pain relief by epidural buprenorphine does not improve diaphragmatic function after upper abdominal surgery.

Abdomen↗
PubMed1996

Diverse effects of calcium antagonists on glomerular hemodynamics.

This study examined the direct effects of calcium antagonists on glomerular hemodynamics. Rabbit afferent (Af-) or efferent arterioles (Ef-Arts) were microperfused in vitro at constant pressure. Ef-Arts were perfused from the distal end of Af-Art through the glomerulus. Increasing doses (10(-10) to 10(-7) M) of nifedipine (Nif), nicardipine (Nic) or manidipine (Man) were added into the lumen of Af- or Ef-Arts preconstricted (by about 40%) with norepinephrine. Although Nif and Nic dilated Af-Arts in a dose-dependent manner, they did not cause any dilation in Ef-Arts. In contrast, Man dilated both Af- and Ef-Arts in a dose dependent manner; Man at 10(-7) M dilated Af- and Ef-Arts by 71 +/- 12% (N = 7) and 38 +/- 3% (N = 6), respectively. Although Man's dilator effect on Ef-Art was not affected by inhibiting nitric oxide (NO) synthesis (N = 6), it was markedly attenuated by eliminating the influence of glomerulus (14 +/- 3% by Man at 10(-7) M, N = 5). These results demonstrate that in addition to dilating Af-Art, Man, but not Nif or Nic, dilates Ef-Art through a glomerulus-derived vasodilator(s) other than NO. Such diverse actions should be taken into consideration when calcium antagonists are used in the treatment of patients with cardiovascular and renal diseases.

Animals↗
PubMed1996

[A case of toxic shock syndrome induced by MRSA after sinus surgery].

We present a case of toxic shock syndrome (TSS) induced by MRSA after sinus surgery. The patient was a 64-year-old woman who had undergone sinus surgery because of chronic sinusitis. Nine days after the surgery, she began to have sore throat, fever, and diffuse erythroderma followed by severe hypotension and renal dysfunction. Culture of sputum, nasal discharge and stool showed MRSA. Blood culture was negative. She was treated with intravenous fluids, catecholamines and antibiotics (vancomycin and fosfomycin). Continuous hemodiafiltration was started because of oliguria. Her condition improved gradually and she was discharged about a month after the onset of her illness. We should recognize that TSS can occur as a fatal complication after nasal surgery.

Chronic Disease↗
PubMed1995

Different effect of hippocampal granule cell destruction on amygdaloid kindling in Sprague-Dawley and Wistar rats.

The hippocampal granule cells receive major inputs via the perforant path from other limbic structures such as the amygdala (AM). In this study, we examined Sprague-Dawley (SD) and Wistar rats, the effect of bilateral destructions of the hippocampal granule cells on the process of AM kindling and kindled AM seizures after completion of kindling. The granule cells were selectively and completely destroyed bilaterally by intra-hippocampal injections of colchicine. The left AM was used as the primary kindling site and the right AM as the secondary site. In SD rats, prior destruction of the granule cells caused a marked delay in the seizure development of both the primary AM kindling and subsequent secondary AM kindling. However, once AM kindling was established in SD rats, the destruction of granule cells was totally ineffective in preventing kindled seizures. In Wistar rats, unlike SD rats, prior destruction of the granule cells failed to change the rate of kindling at the primary and secondary sites. However, Wistar rats showed a transient and marked regression of kindled seizures when the granule cells were destroyed after the completion of AM kindling. In both strains, granule cell destruction had no effect on the re-establishment of kindled seizures at the time of primary-site re-test. These findings suggest that hippocampal granule cells of SD and Wistar rats play different roles in AM kindling.

Amygdala↗
PubMed1995

Distal radioulnar joint subluxation and dislocation diagnosed by standard roentgenography.

The use of standard lateral roentgenography for diagnosing distal radioulnar joint (DRUJ) subluxation and dislocation was investigated. Using a wrist support, bilateral standard lateral roentgenograms of the wrist were obtained in 42 patients with normal wrists and in 56 patients with a unilateral wrist injury. In normal wrists the difference between the radioulnar distance in the right and the left wrist did not exceed 4 mm when the difference in the pisoscaphoid distance was less than 3 mm. Of the 36 patients with wrist injury whose difference in pisoscaphoid distance was less than 3 mm, 15 had a radioulnar distance of 5 mm or more, and computed tomography (CT) confirmed DRUJ dislocation in 14. Concordance between lateral roentgenograms and CT was present in 33 of 36 patients (92%). These results demonstrate the value of a standardized technique for bilateral lateral roentgenography in diagnosing DRUJ subluxation and dislocation.

Adolescent↗
PubMed1995

Effect of hemidiaphragmatic paresis caused by interscalene brachial plexus block on breathing pattern, chest wall mechanics, and arterial blood gases.

We investigated the effects of hemidiaphragmatic paresis caused by interscalene brachial plexus block on breathing patterns, chest wall mechanics, and arterial blood gas tensions using respiratory inductive plethysmography. Ten healthy patients received interscalene block with 20-40 mL 1.5% lidocaine with epinephrine. Rib cage contribution to tidal volume (%RC) increased from 28.9% +/- 9.7% to 50.0% +/- 8.3% (P < 0.01), respiratory frequency (f) increased from 14.6 +/- 3.2/min to 16.3 +/- 2.4/min (P < 0.05), and PaO2 decreased from 84.7 +/- 7.3 mm Hg to 78.0 +/- 9.5 mm Hg (P < 0.05). No significant changes were observed in tidal volume (VT), minute volume (VE), or PaCO2. These results indicated that VT, VE, and PaCO2 were maintained after interscalene block, apparently by increases in f and %RC to compensate for hemidiaphragmatic paresis caused by interscalene block. Nevertheless, PaO2 was reduced, presumably due to increased ventilation-perfusion mismatching. Recognizing that we studied healthy patients, the decrease in PaO2 may be more in patients with cardiopulmonary disease.

Adult↗
PubMed1995

[The dosage of sedative was reduced by patient-controlled sedation during epidural anesthesia].

The dosage of sedatives required for sedation was studied in patients who underwent total abdominal histerectomy under epidural anesthesia using patient-controlled sedation (PCS) and in those with anesthesiologist-controlled sedation (ACS). Patients in experimental groups received 1.0 or 1.5 mg bolus dose of midazolam by their request until desirable sedation was obtained using a computer-controlled device. In control group, anesthesiologists gave 1.5 mg bolus dose of midazolam and repeated until enough sedation was obtained. The total amount of midazolam was 12.15 +/- 3.90 mg (mean +/- SD) in ACS group and showed significant differences from experimental groups (PCS-1.0 group: 7.43 +/- 1.81 mg, PCS-1.5 group: 6.30 +/- 2.81 mg). The level of sedation showed wider variation in PCS groups than in ACS groups. The results suggest that PCS is a technique which allows reduction of sedatives in patients who undergo operation under local anesthesia.

Adult↗
PubMed1995

[Efficacy of epidural neurolysis].

Forty-one patients were treated with epidural neurolysis using 50 % ethyl alcohol 2 ml. Thirty eight patients were suffering from cancer pain and three patients were complaining of chronic benign pain. Alcohol block was repeated 2.3 times (mean) in the same patient. Thirty patients were followed after the treatment. Forty-seven percent of the patients reported 70 % or greater pain relief and 20 % of the patients reported about 50 % pain relief. Duration of pain relief was from 9 days to 203 days with a mean duration of 54 days. Adverse effects were reported 43 % of the patients. There is no miserable adverse effect. Adverse effect reported most was pain with epidural injection of drugs after the alcohol block had been performed.

Adult↗
PubMed1994

Enhancement of cephamycin C production using soybean oil as the sole carbon source.

Vegetable oils were investigated to evaluate their potential to act as the sole carbon source for production of cephamycin C in shake and jar-fermentor cultures. Soybean oil was the best carbon source for cephamycin C production. Bioautography and HPLC analyses showed that cephamycin C was exclusively produced even when soybean oil was used as the sole carbon source. The optimal pH and initial concentration of soybean oil was 7.5 and 7 g/l, respectively. Both pH and the pH-control agent affected cephamycin C production, and among phosphoric acid, acetic acid and sulfuric acid, phosphoric acid was associated with the best production. Soybean oil was slowly consumed after the soluble nitrogen source was consumed. When the initial soybean oil concentration was 7 g/l, cephamycin C production was maximal, 2.0 g/l, which was twice as high as that from starch. The product yield from soybean oil was 4.7 times higher than that from starch. These results show that vegetable oils, which are cheaper than other carbon sources, could be used as the sole carbon source in the production of antibiotics.

Biotechnology↗
PubMed1994

Scaphoid fracture as a "puncher's fracture".

We investigated 18 scaphoid fractures induced by punching. The wrist position while punching was neutral to slight palmar flexion. We postulated that the mechanism of the fracture was caused by the concentration of the external force to the second metacarpus. The forces are then dispersed to the trapezium and trapezoid, which produces shear stress at the waist of the scaphoid. In spite of the differences in mechanism, the location of the fracture was similar to fractured scaphoids caused by wrist extension injuries. Regardless of the wrist positions, the carpal scaphoid is most vulnerable to fracture due to its characteristic morphology.

Adolescent↗
PubMed1994

The roles of the posterior cricoarytenoid and thyropharyngeus muscles in whispered speech.

In order to clarify the nature of the physiological adjustment for the production of whispering, physiological studies were conducted on the glottal and supralaryngeal adjustments during whispering. The results indicate that for the production of whispering there is a necessary relationship between glottal adjustment and supralaryngeal adjustment in terms of the coordination between posterior cricoarytenoid muscle (PCA) and thyropharyngeus muscle (TP). Also, there might be a function switch in our brain which enables the speaking mode to change from ordinary to whispering, using the activation of PCA and TP, as a result of human evolution.

Arytenoid Cartilage↗
PubMed1994

[Combined CDDP-THP-PEP chemotherapy (PTP therapy) for head and neck squamous cell carcinoma--a group study].

A group study of chemotherapy for head and neck squamous cell carcinoma, using CDDP, THP and PEP, was carried out on 32 cases at the department of Otolaryngology, University of Tokyo, and 7 affiliated hospitals. The combined chemotherapy, which we call "PTP therapy", consisted of 30 mg/m2 of THP on day 1, 70 mg/m2 of CDDP on day 2, and 5 mg/body/day of PEP on 4 successive days. The overall response rate was 78.1% (CR: 15.6%; PR: 62.5%). No major side effect was observed in any case. PTP therapy is useful in neoadjuvant chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

[Factors determining the level of PaCO2 during laparoscopic cholecystectomy].

Factors responsible for the elevation of PaCO2 were investigated in 30 patients undergoing laparoscopic cholecystectomy using CO2 gas insufflation. Intraperitoneal insufflation of CO2 gas was performed to the level of 15 mmHg of intraperitoneal pressure in each patient and the following measurements were made: body height, body weight, body surface area (BSA), circumference of abdominal wall, obesity index, body mass index (BMI), operating time, total volume of insufflated CO2 gas, and change of peak inspiratory pressure. Rate of elevation of PaCO2 showed the highest correlation with BSA (correlation coefficient -0.691 [P < 0.01]) followed by body weight, body height, and circumference of abdominal wall. These results suggest that during laparoscopic cholecystectomy using CO2 gas insufflation, the degree of CO2 storage capacity has the highest effect on the elevation of PaCO2.

Adult↗
PubMed1993

[A case of bilateral aldosterone-producing adrenal adenomas].

A 43-year-old female was admitted to our hospital for high blood pressure control. She showed hypokalemia with increased urinary potassium excretion, high plasma aldosterone concentration (33.9ng/dl, normal range; 2-12ng/dl) and reduced plasma renin activity (trace, normal range; 0.83-5ng/ml/hr). Bilateral adrenal tumors were revealed by abdominal computed tomography, and left adrenalectomy and right partial adrenalectomy were performed. Cytochromes p-450 and other enzymes involved in aldosterone synthesis were found predominantly in the tumor portions but not in the zona glomerulosa of the attached adrenals, which histopathologically showed paradoxical hyperplasia. This was a rare case of bilateral aldosterone-producing adrenal adenomas, which we could differentiate from idiopathic hyperaldosteronism by employing immunohistochemical analysis of steroidogenic enzymes.

Adenoma↗
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↗