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Biomedical subjects

C Watanabe

Publications and source records attributed to C Watanabe.

At least 181 records · Page 10Linked to original sources
PubMed1986

The relationship of the increased level of metallothionein with heavy metal levels in the tissue of the harbor seal (Phoca vitulina).

The relationship between age, heavy metal levels, and a heavy-metal binding protein, metallothionein (MT), in the liver and kidney of the harbor seal (Phoca vitulina) was studied. The cadmium (Cd) level in the liver and the Cd, inorganic mercury (I-Hg), and zinc (Zn) levels in the kidney were increased with body length, suggesting an age-related accumulation of these metals. The MT levels determined by an MT radioimmunoassay showed concentrations of 240 +/- 139 micrograms/g in the liver and 343 +/- 219 micrograms/g in the kidney. These MT levels were shown to be correlated with age. The statistically significant relationship of the MT levels with the levels of Cd and Zn in the liver and those of Cd, Zn, and I-Hg in the kidney suggested that the protein is responsible for the sequestration of these metals as already observed in terrestrial animals.

Animals↗
PubMed1985

Kinetic studies on dextransucrase from the cariogenic oral bacterium Streptococcus mutans.

The kinetic mechanism of dextransucrase was studied using the Streptococcus mutans enzyme purified by affinity chromatography to a specific activity of 36.9 mumol/min/mg of enzyme. In addition to dextran synthesis, the enzyme catalyzed sucrose hydrolysis and isotope exchange between fructose and sucrose. The rates of sucrose hydrolysis and dextran synthesis were partitioned as a function of dextran concentration such that exclusive sucrose hydrolysis was observed in the absence of dextran and exclusive dextran synthesis at high dextran concentrations. An analogous situation was observed with fructose-dependent partitioning of sucrose hydrolysis and fructose exchange. Steady state dextran synthesis and fructose isotope exchange kinetics were simplified by assay at dextran or fructose concentrations high enough to eliminate significant contributions from sucrose hydrolysis. This limited dextran synthesis assays to dextran concentrations above apparent saturation. The limitation was diminished by establishing conditions in which the enzyme does not distinguish between dextran as a substrate and product which allowed initial discrimination among mechanisms on the basis of the presence or absence of dextran substrate inhibition. No inhibition was observed, which excluded ping-pong and all but three common sequential mechanisms. Patterns of initial velocity fructose production inhibition and fructose isotope exchange at equilibrium were consistent with dextran synthesis proceeding by a rapid equilibrium random mechanism. A nonsequential segment was apparent in the exchange reaction between fructose and sucrose assayed in the absence of dextran. However, the absence of detectable glucosyl exchange between dextrans and the lack of steady state dextran substrate inhibition indicate that glucosyl transfer to dextran must occur almost exclusively through the sequential route. A review of the kinetic constants from steady state dextran synthesis, fructose product inhibition, and fructose isotope exchange showed a consistency in constants derived from each reaction and revealed that dextran binding increases the affinity of sucrose and fructose for dextransucrase.

Chromatography, Affinity↗
PubMed1985

Cell-matrix interrelation and cell-to-cell connection in the secretory ameloblast layer of kitten teeth.

To investigate the cell-matrix interrelation and the structure and permeability of the junctional complexes of secretory ameloblasts, molar tooth germs from kittens were examined by means of scanning electron microscopy, routine thin sections and freeze-fracture replication. Scanning electron microscopy showed remarkably dissolved growth fronts of enamel in materials that had been fixed with glutaraldehyde and then subjected to EDTA perfusion for 10 min. By the action of EDTA, intercrystallite spaces in rod and interrod enamel were prominently widened, and their longitudinal ends of crystallites displayed irregular and extremely sparse structures. In enamel rods surrounded entirely by interrod enamel, and in enamel rods of the typical key hole shape with successive interrod enamel participation, the most striking dissolution of crystallites occurred at the boundaries between rod and interrod enamel, where broad expanses of rod-sheath spaces were observed. In thin sections, the Tomes processes of secretory ameloblasts occupying the above rods were rectangular or variations of a rectangular shape, respectively; and interameloblast spaces opened to the enamel growth fronts, which corresponded to the junction between rod and interrod enamel. In enamel rods standing in regular rows and showing the typical arcade shape, the centers of the rods were drastically dissolved and exhibited single and deep slits, whereas the boundaries between rod and interrod enamel showed no wide furrows. The Tomes processes occupying such arcade-shaped rods were typically triangular, and the interameloblast space always joined the type-1 face of process, which is responsible for enamel rod formation. Secretory ameloblast possessed two sets of junctional complexes at the proximal and distal ends of the cell body. The distal one was situated proximally to the Tomes process. Freeze-fracture replication demonstrated the functional structures of these junctions: the proximal junction was fascia occludens, and the distal one incomplete zonula occludens with many free-ending tight junctional strands and interstrand spaces or a less developed irregular junction.

Ameloblasts↗
PubMed1985

[Mitral valvular disease secondary to mitral ring calcification: a clinicopathologic study].

Fifteen cases with mitral valvular disease caused by mitral ring calcification (MRC) were observed among 2,800 consecutive autopsy patients more than 60 years of age. They consisted of one man and 14 women whose average age was 86.4 years. All had been diagnosed as having mitral valvular disease during life. For this clinicopathologic study, the cases were categorized as nine cases with mitral regurgitation (MR Group) and six with mitral stenosis (MS Group). Among the 15 cases, phonocardiograms were obtained in 14 and echocardiograms in 6. In addition, 122 cases with MRC, the length of which was 5 mm or more, were selected from 900 recent consecutive autopsies of senile patients, to evaluate the site of calcification and to analyze the ratio of calcification length to mitral valve ring circumference. The following conclusions were obtained: The prevalence of mitral valvular disease due to MRC in the aged was 15/2,800 (0.5%). MR was observed in nine cases and MS in six. Phonocardiograms of the MR Group revealed a holosystolic murmur in seven cases, a late systolic murmur in one, a third heart sound in four and a fourth heart sound in five. In the MS Group, a holosystolic murmur was found in four, a presystolic murmur in four, a diastolic rumble in one, but no opening snap in any case. A diamond-shaped systolic murmur was found in nine cases with MS or MR, suggesting an ejection systolic murmur caused by an associated calcified aortic valve. Echocardiograms showed markedly decreased DDR in five cases and increased echo intensity of the aortic valve in four. Pathologic findings revealed that the mean length of MRC was 36.6 mm in the MR Group and 58.0 mm in the MS Group. The calcification ring ratio (CRR = MRC/MVR X 100) was 50.3% in the MR Group and 69.8% in the MS Group. In the MR Group, MRC involved the anterolateral commissure in three, posteromedial commissure in five, and both in one. In five of six cases with MS, both commissures were involved by MRC. The study of 122 cases with MRC length greater than or equal to 5 mm suggested that MRC occurred first in the middle scallop of the posterior mitral leaflet, and extended to the posterior scallop, subsequently extending up to the anterior scallop, and finally involved the anterior mitral leaflet beyond the commissures.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1985

Effect of fasting on hypoxia tolerance of mice in relation to oxygen consumption and heart rate.

Mice more than 8 weeks old were fasted for 1 or 2 d and challenged by severe acute hypoxia. The hypoxia survival times (ST) were compared to the body weight, oxygen consumption (VO2), or heart rate (HR) of each animal. The duration of fasting was found to be important to determine ST. VO2 or HR were negatively correlated with ST, whether mice were fasted or not. The regression line (InST on HR) in the fed (control) group did not significantly differ from that of 2-d fasted groups, but those of fed and 1-d fasted groups differed. These results suggested that, in fasting for 2 d, the reduction in energy consumption was a major determining factor of hypoxia survival; in 1-d fasting, other factors might operate to determine the tolerance.

Animals↗
PubMed1985

[Pathophysiology and prognosis of acute pancreatitis--early and late prognostic signs].

The purpose of this study is to elucidate the pathophysiology of the acute pancreatitis and set up the criteria for assessing the severity of this disease. One hundred and fifty seven cases of acute pancreatitis were treated at the First Surgical Department of Tokyo University Hospital and its affiliated hospitals. They consisted of 24 severe cases, 76 moderate cases, and 57 mild cases according to our classification. In early stage ten parameters, namely, abnormalities of white cell count, platelet count, hematocrit, lactic acid dehydrogenase, blood urea nitrogen, serum calcium, base excess, PaCO2 and fasting blood glucose and age within 24 hours after admission and X-ray CT scan within 48 hours as early prognostic signs, enabled us to predict severe, moderate, or mild pancreatitis. More than 4 weeks later than the onset of acute pancreatitis, X-ray CT scan, white blood cell count, elevation of serum FDP level, endotoxemia and fall of plasma opsonic index served as good indicators to evaluate the severity of abdominal sepsis. In experimental pancreatitis, CH50 and opsonic index were remarkably decreased at 6 and 12 hours after induction of acute pancreatitis. As the above results, determination of early prognostic signs immediately after onset and late prognostic signs 3-4 weeks after onset is very important to evaluate and manage the acute pancreatitis patients.

Acute Disease↗
PubMed1984

[A clinical study on 164 patients with extensive burn--with special reference to improved survival factors].

One hundred and sixty four patients with extensive burn were treated over 6 years, 1976 through 1981. Clinical data were analyzed, dividing into successive period; Grod: Group I (83 patients, 1976-1978) and Group II (81 patients, 1979-1981). The mean age was 28.9 years, the mean burn area was 52.6% body surface area (% BSA) and Burn Index was 38.7 in group I, whereas in Group II 33.7 years, 56.0% BSA, 41.8, respectively. There are no statistical difference between the two groups. The mortality of the 164 patients was 50.6%. That of Group I was 55.4% and 45.7% in Group II. Excluding patients with almost fatal burns over 70% BSA or over 60 years of age, the former mortality is 33.3% and the latter is 21.3%. When a mortality rate was analyzed in patients with 50-70% BSA and aged less than 60 years in Group I, it was 65.0% and in Group II 36.8%. The main difference in the treatment between the two periods are as follows. Air fluidized beds were used in the latter period. As topical agents, silver sulfadiazine cream was administered in the former period, and silver sulfadiazine cream nitrate was administered in the latter period. Concerning debridement and skin graft, surgery was carried out 2-3 weeks after burn in the former period, while it started within one week in the latter period. In the latter period, active nutritional support and new generation of Cephem were used. These facts reveal that progress in various aspects of the treatments in the latter period have resulted in improvement of the mortality rate.

Adult↗