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Biomedical subjects

M Shimoda

Publications and source records attributed to M Shimoda.

At least 127 records · Page 7Linked to original sources
PubMed1993

Identification of 10-formyltetrahydrofolate, tetrahydrofolate and 5-methyltetrahydrofolate as major reduced folate derivatives in rat bile.

Reduced folate derivatives in rat bile were examined using high-performance liquid chromatography with electrochemical detection (HPLC-ED). Three peaks of folate compounds were observed on the chromatograms. From the retention-time profiles and hydrodynamic voltammograms, and the profiles of ultraviolet (UV) absorbance spectra obtained by HPLC with photodiode array detection, these 3 peaks were identified as 10-formyltetrahydrofolate (10-HCO-H4PteGlu), tetrahydrofolate (H4PteGlu) and 5-methyltetrahydrofolate (5-CH3-H4PteGlu). The rates of bile secretion of 10-HCO-H4PteGlu, H4PteGlu and 5-CH3H4PteGlu were 314 +/- 181, 321 +/- 179 and 449 +/- 198 ng/h (mean +/- S.D.), respectively. 10-HCO-H4PteGlu and H4PteGlu together wtih 5-CH3-H4-PteGlu are found to be the major folate derivatives in rat bile. The nonmethylated folates, 10-HCO-H4PteGlu and H4PteGlu, may also play an important role in folate homeostasis.

Animals↗
PubMed1993

Intracranial complications of hypervolemic therapy in patients with a delayed ischemic deficit attributed to vasospasm.

This investigation has revealed the frequency of various intracranial complications that may result from hypervolemic therapy for a delayed ischemic deficit following subarachnoid hemorrhage (SAH). Among 323 patients with SAH, 112 patients developed a delayed ischemic deficit, 94 of whom underwent hypervolemic therapy. Infarction due to vasospasm was found ultimately in 43 of these 94 patients. Twenty-six patients (28%) developed an intracranial complication during hypervolemic therapy: cerebral edema was aggravated in 18, and a hemorrhagic infarction developed in eight. In 13 of 18 patients with aggravation of edema, delayed ischemic deficit developed within 6 days after the SAH; at that time, a massive new infarction was found in four and edema in 10 patients. After hypervolemic therapy, the 18 patients with aggravation of edema deteriorated rapidly, and 14 of them died. In every case in which hemorrhagic infarction followed hypervolemic therapy, a new infarct was found on computerized tomography (CT) when the delayed ischemic deficit became apparent. Hemorrhagic infarction developed as the delayed ischemic deficit resolved, with one exception. In patients who sustained no complication from hypervolemia, the incidence of both massive new infarction and edema at the time when the delayed ischemic deficit was manifested was only 1%. In 44 of 68 patients who sustained no complication from hypervolemia, the delayed ischemic deficit was manifested on or after the 7th day following the SAH. This study suggests that hypervolemic therapy is contraindicated in a patient who is found to have a massive abnormality on CT at the time when a delayed ischemic deficit is manifested, especially when it occurs within 6 days after the SAH. To avoid hemorrhagic infarction, it is important to discontinue hypervolemic therapy as soon as the delayed ischemic deficit resolves.

Adult↗
PubMed1993

Immunohistochemical study of craniopharyngiomas.

The purpose of this study is to present the histological characteristics of tumor origin and proliferative characteristics of craniopharyngioma. In 25 craniopharyngiomas, the immunoperoxidase technique revealed strong positive reactions for keratin and cytokeratin in cytoplasm of tumor cells. But, immunostaining of keratin and cytokeratin differ from each of layer of craniopharyngioma. The ciliated epithelium in the craniopharyngioma was not stained by keratin, but ciliated epithelium of Rathke's cleft cyst was stained by cytokeratin.

Antigens, Neoplasm↗
PubMed1993

The inhibitory effect of a neuropeptide, ManducaFLRFamide, on the midgut activity of the sphingid moth, Agrius convolvuli.

The effect of ManducaFLRFamide, a neuropeptide originally isolated from the central nervous system of a sphingid moth, Manduca sexta, was examined on the midgut motility of another sphingid moth, Agrius convolvuli. The peptide was shown to suppress the spontaneous contractions of the isolated gut in adult Agrius at low concentrations (> or = 10(-10) M). Immunoreactivity against anti-FMRFamide antiserum was also detected in the brain-suboesophageal ganglion and the retrocerebral neurohaemal organs of the moth. These observations suggest that ManducaFLRFamide, or its closely-related analog, is a neuropeptide which regulates the activity of the digestive tract in Agrius.

Amino Acid Sequence↗
PubMed1993

[Biliary tract infection].

Biliary tract infection is a frequently encountered clinical problem and requires prompt diagnosis, proper understanding of the pathologic manifestations, and adequate treatment. If not managed properly, it can be the cause of disseminated intravascular coagulation and multiple organ failure and its prognosis can be fatal. This paper focuses on two of its representative diseases: acute cholecystitis and acute cholangitis.

Acute Disease↗
PubMed1993

[Experimental study on comparative efficacy of hepatic arterial injection of anticancer agent under temporary occlusion of portal vein].

To compare the efficacy of intra-hepatic arterial infusion of anti-cancer drug under temporary occlusion of portal vein, the following two experiments were performed. 1. VX2 tumor cells (about 1 x 10(5) cells) were transplanted through the superior mesenteric vein of the rabbits, after 2 weeks, 4'-0-Tetrahydropyranyl doxorubicin (2 mg/kg, 2 ml) aqueous solution (THP) was administered into hepatic artery of rabbits with metastatic VX2 liver tumor. 2. THP was injected into hepatic artery under temporary occlusion of portal branch of median left lobe with metastatic liver. Then the THP levels of normal liver tissue and tumor of median left lobe and lateral right lobe. The THP levels of tumor under portal occlusion tended to be about 2.63-fold higher than without occlusion. These results suggest that hepatic arterial injection under portal occlusion is more useful to increase the levels of anticancer agents of metastatic liver tumor.

Animals↗
PubMed1992

Pharmacokinetics and acetylation of sulfa-2-monomethoxine in humans.

In humans sulfa-2-monomethoxine (S) is metabolized by N4-acetylation (39.9 +/- 8.0 per cent). After an oral dose, S is eliminated biphasically (t1/2, 5.2 +/- 1.6 h and 13.2 +/- 3.4 h) which is similar in both fast and slow acetylators. The metabolite N4-acetylsulfa-2-monomethoxine (N4) is eliminated monophasically (t1/2, 30.0 +/- 5.7 h). The intrinsic mean residence time (MRT) of N4 is 33.5 +/- 8.8 h. The mean total body clearance of S is 11.6 +/- 2.7 ml min-1, and the Vdss is 12.3 +/- 1.01. The renal clearance of S during the first day was twice as high as on the following days for two of the six volunteers (8 vs 4 ml min-1). The renal clearance of N4 during the first day, for four out of the six volunteers, was twice as high as on the following days (8 vs 4 ml min-1). The protein binding of S is 95 per cent and that of its conjugate N4 98 per cent. Approximately 80 per cent of the oral dose of S is excreted in the urine as parent drug (41.0 +/- 6.2 per cent) and as N4 acetyl conjugate (39.9 +/- 8.0 per cent).

Acetylation↗
PubMed1992

Discrepancy of xenon concentrations between end-tidal and blood collection methods in xenon-enhanced computed tomographic measurements of cerebral blood flow.

Using xenon-enhanced computed tomography for the study of cerebral blood flow, simultaneous measurements of end-tidal and arterial blood xenon concentrations using the blood collection method were performed to investigate the validity of substituting the end-tidal for the arterial blood xenon concentration. Simultaneous measurement by both methods was performed 68 times in 27 patients. There was no statistical correlation between the arterial blood accumulation rate constant obtained by arterial blood and end-tidal samples, nor between the arterial blood saturation value obtained by the two methods, even when correction was made for age. In brain tissue, all parameters calculated using the end-tidal concentration were lower than those using arterial blood. We therefore suggest that cerebral blood flow values calculated using end-tidal xenon concentration are useful only for qualitative cerebral blood flow mapping, and not applicable to absolute values of cerebral blood flow.

Adolescent↗
PubMed1992

Transdermal delivery and intramuscular injection of trimethoprim/sulphadiazine in sucking piglets.

The pharmacokinetics of a combination of trimethoprim (TMP) and sulphadiazine (SDZ) after topical application to sucking piglets was compared with the pharmacokinetics after intramuscular injection. A long-lasting and fairly constant SDZ/TMP concentration ratio in plasma was obtained after topical application. The mean plasma concentration of TMP ranged from 0.091 to 0.17 micrograms/ml and that of SDZ from 0.72 to 1.1 micrograms/ml for at least 24 h. TMP and SDZ had different half-lives after intramuscular injection. Transdermal delivery of a combined preparation of TMP/SDZ may be usable for colibacillosis of sucking piglets, although the bioavailability of the drugs is poor.

Administration, Cutaneous↗
PubMed1992

Simultaneous determination of tetrahydrofolate and N5-methyltetrahydrofolate in pig plasma by high-performance liquid chromatography with electrochemical detection.

An analytical method for measurement of tetrahydrofolate (THF) and N5-methyltetrahydrofolate (5MF) in pig plasma by the high performance liquid chromatography and electrochemical detection is described. The plasma sample was deproteinized by perchloric acid and the supernatant was analyzed using the following conditions; (a) phenyl bonded phase column as an analytical column; (b) mobile phase consisting of 20 mM acetate buffer (pH 3.6) containing 0.1 mM EDTA and acetonitrile (96.5:3.5, v/v); (c) an applied potential of +300 mV. Under the above condition, both peaks of THF and 5MF in the plasma were well separated. The detection limits of THF and 5MF were 0.15 and 0.13 ng/ml, respectively, at S/N = 3. The recoveries of THF and 5MF from the plasma spiked with standard THF and 5MF were 77.6 +/- 2.1% and 83.0 +/- 1.7% (mean +/- S.D.), respectively.

Animals↗
PubMed1992

Entrapment of the temporal horn: a form of focal non-communicating hydrocephalus caused by intraventricular block of cerebrospinal fluid flow--report of two cases.

In two cases of entrapment of the temporal horn, computed tomography demonstrated the typical appearance of a comma-shaped homogeneous area isodense with water surrounded by a periventricular low-density area. The cause was probably choroid plexitis resulting in obstruction of the cerebrospinal fluid pathway at the atrium. External drainage followed by shunt emplacement is indicated.

Adult↗
PubMed1992

Partial deficiency of cytochrome c oxidase with isolated proximal renal tubular acidosis and hypercalciuria.

We report the case of a 5-year-old boy with mitochondrial cytopathy due to a partial deficiency of cytochrome c oxidase who had isolated proximal renal tubular acidosis and hypercalciuria. The patient developed hypotonia and blepharoptosis and exhibited growth retardation. Biochemical examination of muscle tissue revealed a partial deficiency of cytochrome c oxidase. He was treated with an alkali, hydrochlorothiazide, and indomethacin. After treatment, metabolic acidosis and hypercalciuria improved, and the patient had a catch-up growth phase. This case emphasizes the importance of performing renal tubular functional investigations and treatment in patients with mitochondrial cytopathy, even in the absence of multiple proximal tubular dysfunction.

Acidosis, Renal Tubular↗