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Biomedical subjects

I Watanabe

Publications and source records attributed to I Watanabe.

At least 451 records · Page 25Linked to original sources
PubMed1983

Inhibition and resumption of replicon initiation in X-irradiated mouse L5178Y cells.

Cultured mouse L5178Y cells were irradiated at room temperature with various doses of X-rays, and the rate of 3H-thymidine incorporation was followed for 2 1/2h after exposure. The rate of 3H-thymidine incorporation is affected by two factors; inhibition and resumption of replicon initiation, and chain elongation. A simple method has been developed for estimating the amount of thymidine incorporation which is accounted for by DNA chain elongation after irradiation. This then allows an analysis of the inhibition and resumption of replicon initiation caused by X-rays. The method is based on knowledge of the rate of DNA chain elongation and of the distribution of replicon sizes which are determined by fiber autoradiography. The duration of the inhibition of replicon initiation and the initial slope of the curve showing recovery of initiation were obtained by subtracting the DNA synthesis due to chain elongation from the overall rate of 3H-thymidine incorporation. The interval of depressed DNA synthesis increased with increasing dose of X-rays but only gradually at doses higher than 500 rad. The interval did not exceed 60 min even after 5,000 rad. The initial shope of the curve showing recovery of initiation decreased in a dose dependent manner but very slowly at doses higher than 1,000 rad of X-rays. It appears likely that this initial slope correlates with the relative number of replicons initiating synthesis at the beginning of the recovery period.

Animals↗
PubMed1983

Effect of misonidazole on the radiosensitivity and repair of potentially lethal damage of L5178Y ascites tumor cells.

The radiosensitizing effect of low concentrations of misonidazole was investigated by using L5178Y cells growing as an ascites tumor in DBA-2 mice. The cells were irradiated in vivo with graded doses of X-rays in the presence or absence of 0.1-0.5 mg/g body weight of misonidazole. Then cell survival was assayed in vitro by plating cells in soft agar medium. By analyzing the X-ray survival curves with or without misonidazole, the dose-modifying effects were determined. The results indicated that the slope and shoulder of the survival curves were greatly modified by the treatment with misonidazole. The dose-modifying factor in terms of the D0 ratio between the drug-treated and untreated control cells was increased as the drug concentration was increased. Further, it was revealed that the isoeffect dose ratios, estimated by the linear quadratic equation of Chadwick and Leenhouts, were higher at a low-radiation dose range. This is due to the suppression of the shoulder region of survival curves for the drug-treated cells. The inhibition of the X-ray-induced repair of potentially lethal damage was apparent with 0.1 mg/g body weight of misonidazole. The inhibition became more effective as the drug concentration increased.

Animals↗
PubMed1983

Evaluation of CT in the diagnosis of congenital choanal atresia.

A six-year-old female with congenital bilateral choanal atresia was examined by CT (computed tomography) and contrast radiography. CT clearly demonstrated the existence of choanal atresia, and differentiated osseous stenosis from membranous stenosis in the choanae. CT may be the first choice of radiological examination for the pre-operative diagnosis of congenital choanal atresia.

Child↗
PubMed1983

Biochemical characterization of RNA coliphage MX1.

In order to clarify the taxonomic status of an RNA coliphage, MX1 (a serological intermediate between groups III and IV), we examined (i) read-through protein synthesis in a cell-free protein-synthesizing system, (ii) the peptide map of the coat protein and (iii) the RNA sequence in the 3'-terminal region of MX1 RNA. We found that the characteristics of MX1 were closer to those of group III phages than to those of group IV. For example, the gel elecrophoretic pattern of the protein coded for by MX1 RNA was the same as that of group III phage proteins. Peptide fingerprints of the coat protein of MX1 showed that seven tryptic peptides overlapped with corresponding peptides of Q beta (group III phage), whereas only two peptides overlapped with those of SP (group IV phage). Furthermore, in the base sequence of the first 200 nucleotides from the 3'-end of MX1 RNA, about 70% of the nucleotides were homologous to those of the Q beta RNA, whereas the homology to SP RNA was only 53%. These results suggest that MX1 is more closely related to group III phages than to group IV phages and we propose that it should be assigned to the former group.

Base Sequence↗
PubMed1983

Bacteriophage distribution in human faeces: continuous survey of healthy subjects and patients with internal and leukaemic diseases.

In order to elucidate the ecological role of bacteriophages in the human intestine, we analysed the numbers of coliphages and of coliphage strains present in faecal samples collected from healthy individuals and from patients with certain intestinal diseases. The isolated phages were grouped according to their serological properties. The samples with low phage titres, observed in both healthy subjects and patients, contained mainly temperate phages (many were related to phi 80 and lambda), and those with higher titres, observed in patients, contained virulent phages. From successive surveys of coliphages and their host, Escherichia coli, in faecal samples of each subject, it was concluded that temperate phages are maintained in the human intestine through spontaneous induction of lysogenic bacteria. Qualitative and quantitative differences existed between phages isolated from faecal samples from healthy subjects and from patients. Simultaneous changes in the distribution patterns of coliphages and of the clinical symptoms were observed in a continuous survey of a leukaemic patient in a protective environmental ward.

Coliphages↗
PubMed1983

Distribution of RNA coliphages in Senegal, Ghana, and Madagascar.

The distribution patterns of RNA coliphages (phages) in Senegal, Ghana, and Madagascar were investigated by collecting sewage samples from domestic drainage in November, 1980. In Senegal, among 65 sewage samples collected mainly from Dakar and its vicinity, 14 (22%) contained RNA phages (16 strains). By serological analysis, 13 of 16 strains were found to belong to group III. This is consistent with the distribution pattern of RNA coliphages in tropical and subtropical regions of Asia. In Ghana, however, among 106 samples collected from Accra, Suhum, and their vicinities, only seven (7%) contained RNA phages (seven strains) (groups I, II, and III [1:3:3]). In Madagascar, among 124 samples collected from Antananarivo, Moramanga, and their vicinities, seven (6%) contained RNA phages (seven strains) (groups I, II, III, and IV [1:1:1:4]). In spite of the low isolation frequency, it can be said that Madagascar appears to have a unique distribution pattern (abundance of group IV phages) which differs from that of any other countries we have examined. The generality of the distribution pattern of RNA phages in the tropical region (abundance of group III phages) was thus verified at least in Senegal.

Coliphages↗
PubMed1983

Endotoxin clearance by exchange blood transfusion in septic shock neonates.

The role of exchange transfusion with fresh whole blood in septic shock infants was evaluated. Endotoxin was positive in 8 of 10 infants and completely removed from 6 by exchange transfusion. All 6 infants with negative endotoxins after exchange transfusions survived, but 2 with positive reactions died despite the exchange transfusion. Staphylococcus aureus was cultured in the blood from 2 infants with negative reactions and one of them survived. These findings suggested that the clearance of endotoxin has an important role in exchange transfusion among septic shock neonates.

Endotoxins↗
PubMed1983

Isolation and identification of N2-fixing Pseudomonas associated with wetland rice.

Semisolid yeast extract medium amended with glucose and tryptic soy agar were used to isolate aerobically N2-fixing (C2H2-reducing) heterotrophic bacteria from the root of wetland rice. The isolates were identified as Pseudomonas by gel immunodiffusion and fluorescent antibody techniques in combination with their morphological, cultural, and biochemical characteristics. The N2-fixing H2-utilizing Pseudomonas described in this paper is a new species.

Fluorescent Antibody Technique↗
PubMed1983

The effects of lidocaine and verapamil on overdrive-induced suppression of pacemakers in dogs with complete atrioventricular block.

When the ventricle is electrically stimulated at a faster rate, the cessation of the drive is followed by a temporary suppression of automaticity (overdrive suppression). The effects of lidocaine and verapamil on overdrive suppression were studied in dogs. Lidocaine slowed the ventricular escape rate and prolonged the pause following overdrive; occasionally, it was about twice the next succeeding RR interval. On the contrary, verapamil influenced neither the ventricular escape rate nor the pause following overdrive. It is suggested that lidocaine not only suppresses the automaticity of ventricular escape pacemaker but also induces exit block and that the spontaneous depolarization of the ventricular pacemaker is not slow channel-dependent.

Animals↗
PubMed1983

The fine structure of lamellated nerve endings found in the rat gingiva.

The fine structure of lamellated nerve endings found in the rat gingiva (Sprague Dowly) was examined by electron microscopy. The lamellar corpuscles are localized in the subepithelial portion of the dermal papillae and are circular or oval in shape. The lamellar cells surrounding the nerve terminals demonstrate several modifications in their configuration due to the variable number of cytoplasmic sheets. All the sheets are characterized by the presence of numerous caveolae, small mitochondria, a few cisterns of rough endoplasmic reticulum, microfilaments and microtubules. Serial sections clearly showed that the nerve terminal is subdivided into two or four branches, each of which terminates at different levels of the corpuscle. The laminae branch several times, ultimately connecting with those of neighboring laminae through desmosomes, and are separated from similar processes by an interlaminar substance. The nerve endings contain many mitochondria, neurotubules and small clear vesicles. Cytoplasmic protrusions extend from the nerve terminal into the clefts between the lamellar cells. Small clear vesicles are found in the basal area of the protrusion. The interlaminar spaces are occupied by an amorphous material though collagenous fibrils are conspicuous in some regions.

Animals↗
PubMed1983

Electronystagmography outside the hospital using a pocket-sized electrocardiograph.

It is the desire of the neurotologic clinician to record routinely the nystagmus of patients with vestibular disorders but it is troublesome to have it done frequently. We tried to have patients record their own nystagmus using a portable electrocardiograph. It is pocket-sized and can be operated easily at any time and any place by laymen and often provides beneficial information. When we performed the caloric test on nine patients, we recorded the nystagmus with an ordinary electronystagmograph and with this equipment simultaneously. It has been recognized that the records with a portable electrocardiograph bear close resemblance to the records obtained with an ordinary electronystagmograph. According to the experience in twenty cases of dizzy patients using this recording system, it was concluded that the equipment is useful not only for the diagnosis of dizzy patients, but also for evaluating the effect of drugs and for recommending changes in the mode of living for some patients.

Adult↗
PubMed1983

[ Carcinoma of the remnant stomach following surgical treatment of quadruple cancers].

A case of five metachronous carcinomas is reported. The patient was a 57-year-old male with carcinomas of the stomach, colon, rectum, and lip. A new malignancy was detected in the remnant stomach. This case suggests that frequent follow-ups and cancer screening are required for cancer patient, considering the possibility of subsequent malignancy.

Adenocarcinoma, Mucinous↗
PubMed1983

Assessment of corticosteroid treatment of ethionine pancreatitis in the rabbit.

Corticosteroid treatment of acute pancreatitis has recently been advocated by clinicians. The effectiveness of steroids in the prevention of pancreatitis was studied in the model of ethionine pancreatitis in rabbits. A group of 20 rabbits received ethionine for 6 days. Methyl prednisolone succinate was also given to half of the group for a period of 6 days. Animals were killed on the 7th day; enzyme determinations were done; tissues from the pancreas and liver were obtained, coded, and read as unknown by the pathologist; and tissue damage categorized. Corticosteroid treatment was associated with greater elevation of serum amylase and other enzymes. Light microscopic examination of pancreas and liver revealed no apparent beneficial effect from corticosteroid treatment. The experiment was repeated with special stains being made of liver and pancreas, and electron microscopic studies of five animals in each group was done. Light microscopy showed little difference in cellular damage between the two groups. Electron microscopy revealed less apparent damage in the steroid treated (methyl prednisolone succinate) animals than controls. Steroids may provide minimal protection on a subcellular level from ethionine pancreatitis.

Acute Disease↗