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Biomedical subjects

Y Suda

Publications and source records attributed to Y Suda.

At least 127 records · Page 7Linked to original sources
PubMed1988

[A case of rectal carcinoma that disappeared following preoperative chemotherapy with an FT-207 suppository--confirmed by a thorough histologic examination of the resected specimen].

Presented is the case of a patient, a 56-year-old female, who had complained of bloody stool and constipation. A barium enema and endoscopic examination revealed a tumor (Type 2) with a crater surrounded by a thick embankment, extending from the anterior wall to the left wall of the lower rectum. Biopsy specimens of the tumor disclosed a well-differentiated adenocarcinoma. A FT-207 suppository (1500 mg/day) was administered preoperatively for 50 days (total dose 75 g). On February 16, 1987, the patient underwent an abdominoperineal excision. The resected specimen took on the appearance of a chronic ulcer with an irregular depression, measuring 2.0 x 3.0 cm in size, in the lower rectum. The histology of the lesion also indicated a chronic ulcer, the base of which consisted of fibrosis covered with regenerative mucosa. No cancer cells or nests were demonstrated even serial tissue sections. As far as the rectal carcinoma is concerned, there has been no reported case of its disappearance by preoperative chemotherapy. The above results suggest that preoperative adjuvant chemotherapy can be quite effective against an advanced rectal carcinoma.

Adenocarcinoma↗
PubMed1988

Synthesis of trifluoromethyl analogs of vitamin K as substrates for the liver microsomal vitamin K-dependent carboxylase.

The rat liver microsomal vitamin K-dependent carboxylase catalyzes the carboxylation of glutamyl to gamma-carboxyglutamyl residues in the presence of reduced vitamin K, O2 and CO2. The specificity of the enzyme for the vitamin substrate has been probed by the synthesis of the trifluoromethyl analogs of menaquinone-2 (2-methyl-3-geranyl-1,4-naphthoquinone) and phylloquinone (2-methyl-3-phytyl-1,4-naphthoquinone). The reduced (naphthohydroquinone) forms of the trifluoromethyl analogs of the natural vitamins had no substrate activity but were competitive inhibitors of the reaction with a Ki in the same range as the Km of the normal substrate. The oxidized form of the trifluoromethyl analogs of vitamin K also caused inhibition by a mechanism that could not be established. Under the incubation conditions utilized, fluorine was lost from the trifluoromethyl group by a process that was dithiothreitol and high pH dependent.

Animals↗
PubMed1987

Driven by the same Ig enhancer and SV40 T promoter ras induced lung adenomatous tumors, myc induced pre-B cell lymphomas and SV40 large T gene a variety of tumors in transgenic mice.

Different types of tumors developed in transgenic mice following the introduction of the entire coding region of ras, myc or SV40 large T gene (T) linked to the same regulatory unit, consisting of a human immunoglobulin gene enhancer (Ig) and SV40 early gene promoter (Tp) with a 21-bp repeat. All the 12 transgenic mice harboring the intact T gene developed a variety of tumors including choroid plexus tumor, B cell lymphoma, histiocytic lymphoma, thymoma and others. This suggests that the Ig/Tp regulatory unit has transcriptional activity in these heterologous tissues. With this regulatory unit, myc gene induced solely pre-B cell lymphomas (five out of nine mice). Contrary to our expectation, however, the mutated ras gene induced lung adenomatous tumors in six out of eight transgenic mice over the 10-month observation period; the tumors are histologically comparable to adenocarcinomas in man. The tumors developed as early as 4 weeks after birth and the introduced ras gene was as efficiently expressed in both normal and neoplastic bronchioloalveolar epithelial cells as in normal lymphoid cells. An unidentified secondary event thus appears to be necessary for these ras-expressing cells to become neoplastic, as observed for myc (Leder et al., 1986). In a variety of tumors induced by Ig/Tp-T, on the other hand, T gene was expressed only in the tumor cells, but not in normal cells. Thus, derepression of T gene in normal cells appears to be closely related to their malignant change as observed in development of pancreatic acinar cell tumors by the T gene (Ornitz et al., 1985). These results suggest that ras and myc oncogenes penetrate differentially specific types of cells, while the SV40 T gene is tumorigenic in a variety of cell types.

Adenoma↗
PubMed1987

Inhibitory effect of 2,4-dihydroxyphenylacetylasparagine, a common moiety of spider toxin, on glutamate binding to rat brain synaptic membranes.

2,4-Dihydroxyphenylacetylasparagine (2,4-DHPA-ASN), a common moiety of molecules of spider toxins, was shown to inhibit L-[3H]glutamic acid binding to rat brain synaptic membranes in a dose-dependent manner. The inhibitory effect of 2,4-DHPA-ASN was almost the same as that of intact spider toxin isolated from Nephila clavata, but significantly higher than that of 2,4-dihydroxyphenylacetic acid (2,4-DHPA). In addition, neither 2,4-dihydroxybenzoic acid nor the isomers of 2,4-DHPA suppressed the glutamate binding. These results suggested that 2,4-DHPA might be the functional part and asparagine in the molecules of spider toxins seemed to cause increasing affinity toward the recognition site of glutamate binding.

Animals↗
PubMed1987

Molecular action mechanism of spider toxin on glutamate receptor: role of 2,4-dihydroxyphenylacetic acid in toxin molecule.

Joro spider toxin (JSTX) isolated from Nephila clavata was shown to inhibit L-glutamate binding to rat brain synaptic membranes in a dose-dependent manner. 2,4-Dihydroxyphenylacetic acid (2,4-DHPA), a common moiety of spider toxins, also inhibited specifically L-glutamate binding at a concentration similar to that of the toxin. The binding activity inhibited by 2,4-DHPA or JSTX was recoverable on addition of ferric compound. These results suggest that 2,4-DHPA is a functional moiety in the toxin molecule and the biological action of spider toxin is explained by direct interaction with an Fe-S center which is known to play an important role for the glutamate binding.

Animals↗
PubMed1987

Mouse embryonic stem cells exhibit indefinite proliferative potential.

The proliferative potential of embryonic stem cells was examined. In contrast to the current concept of the finite life-span being the hallmark of normal cells, we have been able to maintain these embryonic stem cells in vitro up to about 250 cumulative doublings with no indication of "crisis" or transformation. These cells could be considered normal on the basis of: (1) their apparently normal diploid karyotype, (2) their ability to extensively colonize embryos without causing tumors and developmental anomalies, and (3) their ability to form normal gametes when differentiated into the germ-line. These results suggest that embryonic stem cells prior to differentiation into germ and somatic cells are indeed immortal.

Animals↗
PubMed1987

Blood lactate parameters related to aerobic capacity and endurance performance.

The relationships among four descriptors of lactate increase: lactate threshold (LT) (the VO2 at which blood lactate concentration begins to increase above the resting level during an incremental exercise test), LT1 (the VO2 at which blood lactate increases 1 mM above the resting level), LT2 (the VO2 at which blood lactate concentration reaches a fixed value of 2 mM), onset of blood lactate accumulation (OBLA; the VO2 at which blood lactate reaches a concentration of 4 mM), were compared with aerobic capacity (VO2max) and 12 min running performance in 19 untrained female students. The VO2 (+/- SD) of LT, LT1, LT2, OBLA, and VO2max were 14.5 +/- 3.7 ml X kg-1 X min-1, 22.5 +/- 4.3 ml X kg-1 X min-1, 22.2 +/- 4.5 ml X kg-1 X min-1, 30.3 +/- 5.2 ml X kg-1 X min-1 and 36.0 +/- 5.1 ml X kg-1 X min-1, respectively. The mean (+/- SD) distance covered in the 12 min running was 2356 +/- 160 m. The results were as follows: 1) the lactate parameters (i.e. LT, LT1, LT2, and OBLA) were highly correlated with each other. 2) all the lactate parameters were related to VO2max and endurance running performance with a high correlation coefficient. Of the four descriptors of lactate change with exercise, LT correlated best with VO2max and endurance running performance compared to LT1, LT2 and OBLA. It is concluded that lactate threshold is the best index for aerobic capacity and endurance running performance.

Adult↗
PubMed1987

[A case of trigeminal neurinoma with marked extracranial extension].

A case of trigeminal neurinoma with marked extracranial extension is reported with a review of the literature. A 60-year-old female noticed numbness over the left side of the face during the proceeding 15 years. Two years prior to admission, she began to complain of itching and lancinating pain at the left lateral aspect of the nose. Neurologic examination on admission revealed diminished corneal reflex on the left side and hypesthesia in the distribution of the left trigeminal nerve. There was no weakness or atrophy of the ipsilateral masticatory muscles. The remaining cranial nerves and cerebellar functions were normal. Craniograms showed destruction of the left petrous apex, enlargement of the left superior orbital fissure and an extensive bone defect in the floor of the left middle cranial fossa. CT disclosed a huge heterogeneously enhancing mass lesion in the left middle cranial fossa, which extended posteriorly into the left cerebellopontine angle and inferiorly into the pterygoid and infratemporal fossae. Cerebral angiograms revealed medial displacement of the left internal cerebral artery in the ganglionic, cavernous and supraclinoid portions, and elevation of the left middle cerebral artery in the sphenoidal portion. Although the left meningohypophyseal trunk was dilated, no tumor stain was observed. A transantral biopsy specimen provided the diagnosis of neurinoma with Antoni type A tissue. The patient was followed up at the outpatient clinic as radical operations were not agreed upon. Eight cases of trigeminal neurinoma with extracranial extension are reviewed including the presented case. There were two males and six females, and the age varied from 16 to 65 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Cranial Nerve Neoplasms↗
PubMed1986

Single photon emission computed tomography of brain tumors with 201TIC1.

Single photon emission computed tomography (SPECT) with 201TIC1 was performed in 27 patients with brain tumors. Findings on SPECT were compared with those on planar images, computed tomography (CT) and, in 4 cases, magnetic resonance imaging (MRI). At SPECT the tumors were shown as areas with higher accumulation of the tracers than the surrounding brain tissue in 24 cases and a better discrimination was obtained than in planar images. Deep-seated lesions were especially visualized. In some cases SPECT defined lesions that were not clearly delineated on CT or MRI. SPECT with 201TlCl can be of clinical use in the diagnosis of brain tumors.

Brain Neoplasms↗