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Biomedical subjects

A Yamada

Publications and source records attributed to A Yamada.

At least 325 records · Page 18Linked to original sources
PubMed1994

Radiotherapy for superficial esophageal cancer.

PURPOSE: The results of definitive radiotherapy for superficial esophageal cancer is presented. METHODS AND MATERIALS: Twenty-one patients with superficial squamous cell carcinoma of the esophagus were treated by definitive radiotherapy with megavoltage x-rays in Tokyo Women's Medical College from 1975 to December 1990. Eight patients refused surgery and 13 patients were considered to be unsuitable for surgery due to advanced age or morbid conditions such as severe pulmonary dysfunction, myocardial infarction, liver cirrhosis, and other cancer. Radiotherapy was performed using 1.8-2.2 Gy fraction dose, 5 times a week and with a total dose of 50-76 Gy/5-7 weeks (median; 70 Gy). Three patients received intraluminal radiotherapy in addition. Combined chemotherapy was performed in four cases, and three cases received it before radiotherapy and one case after radiotherapy. RESULTS: Overall survival rate was 40.8%, and the cause-specific 5-year survival rate was 61.7%. The 5-year survival rate of the group with morbid conditions was 17.5%, but that of the group without morbid conditions was 60.6%. Seven patients developed recurrence (primary site: 3, lymph nodes: 3, lung: 1) and one patient revealed multicentric cancer of the hypopharynx with wide submucosal spread of the esophagus at 28 months after radiotherapy. No patient developed severe side effect due to radiotherapy. CONCLUSION: Definitive radiotherapy with or without chemotherapy can be applied as an alternative therapy to surgery for superficial esophageal cancer, even for the operable patients under good general condition.

Aged↗
PubMed1994

Effect on fusion induction of point mutations introduced into the F protein of mumps virus.

We have tested the effect of substitution of an amino acid at position 195 of the F protein of mumps virus on cell-to-cell fusion caused by the virus. Introduction of amino acids with aromatic side chains into this position resulted in reduction of fusion induction. Furthermore the F protein was not cleaved when the amino acid at this position was substituted by several amino acids, suggesting that the amino acid at this position was essential to keep the tertiary structure of the protein that might be required not only for proper folding of the protein but also for induction of membrane fusion.

Mumps virus↗
PubMed1994

Pharmacological characterisation of NK1 receptor antagonist, [D-Trp7]sendide, on behaviour elicited by substance P in the mouse.

An analogue of sendide, [D-Trp7]sendide, was newly synthetized and evaluated as a putative NK1 receptor antagonist in a mouse behavioural test. Effects of [D-Trp7]sendide on the scratching, biting and licking response induced by substance P (SP), neurokinin A (NK A) and neurokinin B (NK B) was studied after intrathecal injections. When administered simultaneously with SP, an endogenous agonist for NK1 receptors, [D-Trp7]sendide inhibited the behavioural response to this tachykinin in a dose-dependent manner with ID50 value of 11.0 pmol/mouse. The behavioural response elicited by other NK1 receptor agonists, septide and physalaemin, was reduced significantly by a small dose (32.0 pmol) of [D-Trp7]sendide. Large doses (nmol order) of [D-Trp7]sendide were needed to reduce the characteristic behaviour of NK A, an NK2 agonist, NK B, an NK3 agonist and eledoisin, an NK2/NK3 agonist. The duration of the antagonistic effect of [D-Trp7]sendide was relatively longer. In a [3H]labeled SP binding assay using mouse spinal cord membranes, [D-Trp7]sendide potently displaced [3H] labeled SP binding with a Ki value of 0.023 +/- 0.007 nM, which was approximately 140 and 9400 times more potent than that of unlabeled SP and CP-96,345, respectively. These findings suggest that [D-Trp7]sendide interacts selectively with the NK1 receptor in the mouse spinal cord as assayed by the receptor binding and SP-induced behavioural tests.

Amino Acid Sequence↗
PubMed1994

Cooling-induced retrograde amnesia reflexes Pavlovian conditioning associations in Limax flavus.

The relationships between cooling-induced retrograde amnesia and associations in Pavlovian conditioning in the terrestrial mollusk Limax flavus were studied. In the first experiment, the slugs were conditioned to avoid carrot odor and the experimental conditions required for amnesia induction were studied. Memory reactivation before cooling was found to be necessary for amnesia induction and the induced amnesia was selective for the reactivated memory. In the subsequent experiments, slugs were conditioned to avoid both carrot and cucumber odors using one of three Pavlovian conditioning paradigms, namely two-independent first-order conditioning, phase-2-sequential second-order conditioning and phase-2-simultaneous second-order conditioning, after which amnesia was induced by cooling immediately after presentation of one of the conditioning odors. The amnesia pattern induced differed depending upon the conditioning procedure used, which indicated that amnesia induction was related closely to stimulus associations in slugs. The possible role of cooling-induced retrograde amnesia as a tool for studying memory associations is also discussed.

Amnesia, Retrograde↗
PubMed1994

Sequence variation within the carboxyl terminus of the nucleoprotein gene of mumps virus strains.

BACKGROUND: On rare occasions, clinically apparent mumps virus infection and meningitis can be caused by vaccine virus as well as wild type strains. This has been shown by nucleotide sequencing of short regions of the viral genome. OBJECTIVES: We wished to confirm and extended these findings by investigating for strain differences within the carboxyl terminus of the nucleoprotein (NP) gene, which is known to be highly variable amongst paramyxoviruses in general. STUDY DESIGN: A 576 bp carboxyterminal fragment of NP was amplified by reverse transcriptase (RT) PCR from several different strains and was sequenced directly. RESULTS: Three Urabe vaccine variants and five clinical isolates previously classified as Urabe strains revealed the same carboxyterminal pattern for NP. Three other isolates and the Leningrad-3 vaccine strain showed characteristic differences of up to 5% compared to the Urabe strains, with U/C substitutions being predominant. CONCLUSIONS: The carboxyterminal sequence of NP varies significantly between mumps virus strains such that it can be used for differentiating between vaccine and wild-type isolates.

Journal Article↗
PubMed1994

Evaluation of laser Doppler flowmetry in renal transplantation.

Renal grafts are presently evaluated based on the surgeon's observation of the organ microcirculation. Effectiveness of organ microcirculation has traditionally been accomplished through evaluation of the appearance of the graft. Laser doppler flowmetry (LDF) has been suggested as a possible means to determine graft effectiveness. Renal grafts in 46 transplants were studied using LDF and the technique was evaluated. It was found to be a useful technique for monitoring effectiveness of grafts.

Evaluation Studies as Topic↗
PubMed1994

Long-term follow-up study of browlift for treatment of facial paralysis.

Browlift for patients with irreversible paralysis of the frontalis muscle was evaluated in a review of 40 patients who had undergone follow-up studies for durations of more than 3 years. The procedure consists of a lazy S-shaped excision above the upper border of the eyebrow and upward fixation of the lower skin margin. The results were as follows: (1) The percentage of patients for whom symmetrical positioning of the eyebrow was achieved was 65%. (2) The greater the preoperative severity of ptosis, the more often did recurrence occur. (3) Recurrence progressed rapidly during the first postoperative year, but thereafter recurrence was seen only in those patients in whom the affected eyebrow was still in a position higher than its counterpart. (4) No relationship could be seen between age at the time of surgery and postoperative position of eyebrow. (5) Improvement in contraction of the visual field was seen in 85% of patients postoperatively, and complaints were eliminated in 50%. (6) Careful preservation of the sensory nerve is required. (7) The postoperative scar was acceptable. This procedure is a simple and effective method of correction of paralytic ptosis. Although a degree of skill is required to obtain satisfactory results and a surgical scar remains at the upper border of the eyebrow, the advantages of the procedure surpass its disadvantages. It is believed that this method should be used more often in the treatment of facial paralysis.

Adolescent↗
PubMed1994

Treatment of brachymetatarsia by callus distraction (callotasis).

Callus distraction (callotasis) has already become a popular procedure in the lengthening of limbs. With the development of a small device, it can also be applied to the hand or foot, thus providing benefits in the treatment of brachymetatarsia. Four toes of 3 patients with brachymetatarsia of the fourth toe were treated by this method, and excellent elongation of from 17.50 to 32.55 mm (average, 23.71 mm) was acquired. The treatment period ranged from 78 to 141 days (average, 112.5 days). More time was required in the earlier cases, but the most recent took only 11 weeks. The optimal distraction rate is considered to be 0.35 mm per half-day. Reshortening after treatment ranged from 3.6 to 5.5 mm (average, 4.7 mm), or from 15% to 26% (average, 20.5%) of the distracted length. About 90% of the resorption was observed within 1 month, except in a case that involved a postoperative fracture, and no resorption was seen after 2 surgical months. Regarding complications, subluxation of joints was seen in 2 patients and a postoperative fracture in 1 patient. Subluxation was caused by tendons resisting elongation. The procedure is described, representative cases are illustrated, and problems encountered are discussed.

Adolescent↗
PubMed1994

Tendinocutaneous free flap transfer to cover an extensive skin-tendon defect of the dorsum of the hand: case report.

The combined loss of skin and tendons after avulsion or degloving injuries continues to be a challenging problem. A 51-year-old man sustained an extensive avulsion injury of the dorsal hand. He underwent reconstruction with a vascularized tendinocutaneous free flap transfer from the dorsum of the foot and was followed for over a year. The functional and aesthetic results were satisfactory.

Foot↗
PubMed1994

Versatility of a free inferior rectus abdominis flap for head and neck reconstruction: analysis of 200 cases.

Between 1984 and 1991, 200 inferior rectus abdominis muscle and musculocutaneous free flap transfers were performed for reconstruction of defects or deformities resulting from removal of cancer in the head and neck region. Primary reconstruction was performed in 190 of 200 cases (95 percent), and secondary reconstruction in 10 cases (5 percent). The most common indication was tongue cancer in 78 patients, followed by cancer of the oropharynx. Total flap necrosis occurred in 10 cases (5 percent) and partial necrosis in two cases (1 percent). Donor-site morbidity was minimal. One of the distinct advantages of this flap is that the volume of the muscle and/or the fatty tissue attached to a given skin paddle can be readily adjusted to suit individual requirements. This flap has proven particularly useful for complex or large tissue defects in the head and neck region.

Adolescent↗
PubMed1994

Long-term follow-up of nerve conduction velocity in cross-face nerve grafting for the treatment of facial paralysis.

Motor nerve conduction velocity in a sural nerve graft crossing the face for the treatment of facial paralysis was measured postoperatively for more than 3 years. Forty-three cases of free gracilis muscle transplantation combined with a cross-face nerve graft were evaluated. The cross-face nerve graft was stimulated at two sites more than 5 cm apart by bipolar stimulating electrodes, and conduction velocity was calculated by dividing the length of this segment by the difference between the latencies of the evoked action potentials recorded from the grafted muscle. A tendency toward increase in motor nerve conduction velocity was noticed even 3 years after the sural nerve graft. This suggests that the grafted nerve has the potential to recover over a long period of time. The average velocity in measurements after the third postoperative year was 40.5 +/- 6.2 m/s (mean +/- SD), which corresponds to the lower limit of the normal value for the sural or facial nerve.

Adolescent↗
PubMed1994

Free neurovascular muscle transplantation for the treatment of facial paralysis using the hypoglossal nerve as a recipient motor source.

Seventeen cases of free-muscle transplantation using the hypoglossal nerve as a recipient motor nerve for the treatment of long-standing or irreversible facial paralysis are reported with details of a follow-up study. The muscle, usually the latissimus dorsi muscle, is transferred to the cheek with microvascular anastomoses. The muscle's motor nerve is sutured to the hypoglossal nerve. There are three classifications of hypoglossal nerve sectioning: total section, central section, and lower section. The results were compared on the basis of these three methods, leading to the recommendation that branches of the hypoglossal nerve diverging inferiorly to innervate the suprahyoid muscles be utilized as a recipient motor source. This method permits acceptably natural movement of the grafted muscle without functional disability of the tongue. Good candidates for this procedure are considered to be those patients for whom muscle transplantation combined with a cross-face nerve graft cannot be adopted because of bilateral paralysis or surgical intervention on the healthy side of the face or who are so old that the long two-stage operation holds no hope for them.

Adult↗
PubMed1994

Tissue expansion in facial reconstruction.

The tissue expansion technique is advantageous in facial reconstruction because it makes it possible to resurface even wider defects with neighboring skin similar in color and texture and superior to skin obtained elsewhere, thereby surpassing conventional methods. However, there still remain some problems relating to procedural details, such as the selection of tissue expanders and sites of their insertion; the design, elevation, suturing, and fixation of the expanded flap; and the management of free margins such as the lower lip and lower eyelid. In each case, some modification is required with respect to the status of the defect. The experiences encountered in a series of 23 patients are described, with illustration of several representative cases, and advantages and problems are discussed.

Adolescent↗
PubMed1994

Sialoglycoproteins that bind influenza A virus and resist viral neuraminidase in different animal sera.

Sialoglycoproteins that are resistant to degradation by viral neuraminidase can effectively neutralize influenza A viruses, because they bind irreversibly to the viruses. To detect such proteins in animal sera, we developed an immunochemical assay based on Western blotting techniques. We assessed the binding activity of sialoglycoproteins in sera from nine different animals toward the A/Aichi/2/68 (H3N2) and A/PR/8/34 (H1N1) strains of influenza virus, with or without viral and bacterial neuraminidase treatment. Using this assay, we found that animal sera contain a spectrum of sialoglycoproteins defined by differing abilities to bind influenza A viruses and to resist the viral neuraminidase. Structural analysis of these inhibitors would provide useful information for the development of anti-influenza virus compounds.

Animals↗
PubMed1994

Inhibition of topoisomerase II by a novel antitumor cyclic depsipeptide, BE-22179.

BE-22179, a novel cyclic depsipeptide antibiotic having two 3-hydroxyquinoline moieties, inhibited the DNA-relaxing activity of L1210 topoisomerase II completely at 0.08 microM. This effect was far stronger than that of VP-16. However, it did not show any marked effect on topoisomerase II-mediated DNA cleavage. BE-22179 was ineffective in inhibiting the DNA relaxation by topoisomerase I at concentrations up to 10 microM, but showed DNA-intercalating ability (DNA unwinding) at 30 microM. The structure of BE-22179 is quite novel for a topoisomerase II inhibitor. Echinomycin, a quinoxaline antibiotic structurally related to BE-22179, interfered with DNA relaxation by topoisomerase II, though the effect was not due to inhibition of the catalytic activity of topoisomerase II but to conformational change of DNA based on its intercalation into DNA. Therefore, the potent inhibitory activity on topoisomerase II might not be a common activity of quinoxaline antibiotics, but might rather be specific to BE-22179. BE-22179 prevented DNA synthesis as well as RNA synthesis in L1210 cells and inhibited the growth of the cells. However, it remains unclear to what extent the topoisomerase II inhibition was responsible for the cytotoxicity of BE-22179.

Animals↗