PubMed Health⌕ Search

Biomedical subjects

R Hamada

Publications and source records attributed to R Hamada.

At least 37 records · Page 2Linked to original sources
PubMed1988

Comparative biochemical and morphometric studies on corneal wound healing.

Comparative biochemical and morphological studies were carried out on wounded corneas in order to correlate biochemical findings with morphometric observations during the healing process. Experimental production of corneal wounds, biochemical determinations and quantitative morphometric studies are described in an attempt to correlate corneal matrix macromolecules biosynthesis during the healing process with the morphological modifications of the tissue. The central part and the peripheral part of the corneas were examined separately and compared to the central and peripheral parts of the controlateral corneas. The DNA content of the central portion of the wounded corneas progressively increased and reached after 60 days the same level as the corresponding portion of the controlateral corneas. The DNA contents of the peripheral portions of wounded and controlateral corneas are persistently higher than the DNA contents in the central portion. In peripheral portions of wounded corneas the DNA content is higher than in controlateral corneas and continues to increase steadily during the 60 days of experimentation. Cell density, as determined by morphometry, increased also during that period. The differences between the evolution of the DNA contents and cell density curves may be attributed to variations in cell sizes. The collagen content, estimated from hydroxyproline determinations remained lower in the wounded corneas as compared to the controlateral corneas, even 60 days after operation. This was true for the central as well as for the peripheral portions, suggesting a collagenolytic process as a result of wounding. This is confirmed by morphometric evaluation of fiber density.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

The clearance of manganese chloride in the primate.

Two macaque monkeys inhaled trace amounts of 54MnCl2 for 30 min. Subsequently the chest, head, and fecal radioactivity were monitored for over a year. The chest data curve required a sum of three exponential terms, with half-times ranging from 0.2 to 187 days, to attain a satisfactory fit. Head levels peaked 40 days after acute inhalation exposure and remained elevated for over a year. The excretion of manganese through the feces was best described by a sum of two exponentials. One had a half-time of less than 1 day and the second had a half-time of 50 to 60 days. A third macaque received a 6-week continuous exposure to 54Mn through a subcutaneous osmotic pump. With this route, manganese clearance from the head occurred at a faster rate than after acute inhalation exposure. Fecal elimination following continuous subcutaneous exposure resembled that following acute inhalation. Kinetic analyses suggested that the long half-times of manganese in the head following inhalation reflected both slow disappearance from the head and replenishment from other depots.

Animals↗
PubMed1987

A comparison of statistical outcome variables in extremely low birth weight infants.

Three different summary statistics of developmental outcome are described. These include the "handicap ratio" (handicapped individuals divided by survivors), the "handicap rate" (handicapped individuals divided by live births for that birth weight group), and the "handicaps per 10,000 live births" (handicapped individuals divided by 10,000 live births for a geographic region). An analysis of these statistics was undertaken using a sample of extremely low birth weight (ELBW) (less than 1,001 g) infants born in Hawaii during the period of 1975-1981. The results of this study showed a poor correlation between these summary statistics. The results suggest that these statistics represent different aspects of outcome in the ELBW infant. Suitable uses for each of these variables is discussed.

Birth Rate↗
PubMed1980

Blood vitamin B1, transketolase and thiamine pyrophosphate (TPP) effect in beriberi patients, with studies employing discriminant analysis.

In recent years, many cases of beriberi have been reported throughout Japan. One may assume that a great many healthy subjects suffer from a subclinical thiamine deficiency. The present study was carried out in order to examine thiamine status in 21 beriberi patients and 674 apparently normal subjects. In the beriberi patients the total vitamin B1 in whole blood and transketolase activity in the hemolysate were significantly lower, and the thiamine pyrophosphate effect was significantly higher, compared to normal subjects. However, these two groups could not be clearly separated by these biochemical parameters because of significant overlap. On analyzing the results of these biochemical parameters by discriminant analysis, beriberi could be diagnosed with an accuracy of 87,7%. Thus, vitamin B1 levels in blood, transketolase activity and the thiamine pyrophosphate effect in the hemolysate are useful biochemical indices for the diagnosis of beriberi. Above all, the thiamine pyrophosphate effect proved to be the most effective parameter in distinguishing the beriberi group from normal subjects.

Adolescent↗