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Biomedical subjects

T Nakamoto

Publications and source records attributed to T Nakamoto.

At least 199 records · Page 11Linked to original sources
PubMed1983

Cataract formation in newborn rats from feeding a liquid protein diet during gestation.

Liquid protein diets have been widely used in the United States to control weight gain. Pregnant rats were fed a standard casein diet in which liquid protein was substituted for the protein portion; all other necessary nutrients were supplied. The average incidence of cataracts in the offspring from mothers fed liquid protein was 25%. Offspring born with cataracts were successfully raised. The results suggest that nutrition may play an important role in cataract formation in newborns, and that the use of liquid protein during pregnancy may be related to ocular abnormalities in the offspring.

Animals↗
PubMed1983

Complete deficiency of adenine phosphoribosyl transferase: report of a new family.

We report a case of 2,8-dihydroxyadenine urinary lithiasis with complete deficiency of adenine phosphoribosyl transferase. Adenine phosphoribosyl transferase activities in the erythrocytes, lymphocytes and granulocytes of the patient's family also were determined. The propositus and her younger brother were homozygotes for adenine phosphoribosyl transferase deficiency and her parents were heterozygotes. This is the third family with this disease to be reported.

Adenine↗
PubMed1983

The effect of prenatal protein-energy malnutrition on the development of mandibles and long bones in newborn rats.

To evaluate the role of gestational protein-energy malnutrition on fetal hard-tissue growth and metabolism, we measured several variables in the growth centres of mandibles and long bones of newborn rats. Control pups and pups of malnourished dams had approximately the same extent of reduction in body-weight, mandibular weight and long-bone weight. The malnourished group had more cells in the mandible although cell size was the same as that of controls. In contrast, in the long bones, the malnourished group had fewer cells than did controls whereas cell size was unchanged. Calcium content was the same in long bones of both groups, but was less in the mandibles of pups from malnourished dams. Ca metabolism as measured by 45Ca uptake was unchanged in the long bones, but was increased in the mandibles of the malnourished group shortly after birth. Calcification patterns at birth in these bones correlated well with alkaline phosphatase (EC 3.1.3.1) activity. These findings indicate that the mandibles and long bones of offspring are affected differently by protein-energy malnutrition during the mother's gestation. Prenatal nutritional stress resulted in a disturbance of the pituitary-adrenal system. Increased adrenal corticosterone could possibly be related to the different observed changes in bone metabolism.

Animals↗
PubMed1983

Effect of liquid protein diet on collagen metabolism of the gingiva of young rats.

The effects of liquid protein diet (LPD) on gingival collagen metabolism were evaluated in young rats. Experimental animals received a LPD, while pair-fed and ad libitum groups received a 20% casein diet. Prior to sacrifice at days 23, 35 and 48 post-partum, animals from each group were injected with C14-proline. Gingival tissues from the palate were excised and analyzed for collagen content and collagen synthesis. Results of body-weight changes at day 48 showed a 20% decrease in the LPD group, while pair-fed and ad libitum groups increased 47% and 267%, respectively. Collagen content per gram of gingiva was not significantly different among the three groups. Gingival collagen synthesis, however, did show significant differences among the three groups. It was concluded that while LPD effects on the overall body condition were profound, LPD exerts minimal effect on gingival collagen metabolism in young rats.

Alopecia↗
PubMed1983

[Clinical study of male infertility].

A statistical analysis was performed on infertile male patients who visited our urological clinic between Jan. 1976 and Dec. 1981. The incidence of infertile male was 9.9% of the total male out-patients. Age distribution of most of the patients ranged from 25 to 34 years old. Infertile period was most commonly within 5 years after they had married. In semen analysis, the cases of azoospermia and oligozoospermia (less than 50 x 10(6)/ml) accounted for 80% of all the infertile males. Testicular histology showed hypospermatogenesis or "Sertoli cell only" in most patients (more than 84.2%) who received testicular biopsy. Decrease in testicular volume was accompanied by an increase in the serum levels of luteinizing hormone and follicle stimulating hormone, but there was no relationship between testicular volume and testosterone. Most of the patients with a testicular volume of less than 12 ml were azoospermic. This suggests that there may be a suppression of spermatogenesis in small testes.

Adult↗
PubMed1982

The effects of retinoic acid on the growth of mandible and long bone in fetal rats.

Timed-pregnant rats were injected with a total of 90 microgram of retinoic acid from day 13 until delivery. Other pregnant groups were given either a total of 390 microgram of retinol from day 5 or a total of 270 microgram of retinol from day 13 until delivery. Although the weight gains and food intake of the dams during gestation showed no difference between groups, the long bones were slightly heavier in pups born from retinoic acid-injected dams. Total collagen content in both mandibles and long bones did not show differences between retinoic acid- and retinol-injected groups, but collagen synthesis in both bones was greatly increased in the retinoic acid-injected groups. Calcium content of the mandible in the retinol-injected group from day 13 of gestation was increased, whereas 45Ca uptake of long bone of this group was increased. Retinoic acid, when injected in physiological doses during gestation, may have some effects on the organic phase of bone, long bones being slightly more sensitive to retinoic acid than the mandibles.

Animals↗
PubMed1982

Effects of prenatal malnutrition on development of oral tissue in neonatal rats.

The effects of prenatal malnutrition on the growth of incisor and molar tooth germs and tongue were investigated in newborn rats. Compared with the results on the young of well-nourished mothers, the young of the malnourished animals had fewer and smaller cells in the molar tooth germs and fewer cells in incisor tooth germs. The tongue of the malnourished animals had fewer but larger cells. 45Ca uptake studies and alkaline and acid phosphatase activities suggested that prenatal malnutrition affected incisor and molar tooth germs in different ways. Alkaline phosphatase activity in the tongue did not differ between dietary groups. The results indicate that an adequate protein intake is extremely important for the healthy development of the teeth and tongue of the offspring.

Acid Phosphatase↗
PubMed1979

Kinetics of initiation of bacterial protein synthesis.

The 30S initiation complex, formed with the 30S ribosomal subunit, mRNA, and fMet-tRNA, has been shown by kinetic analysis with limiting concentrations of Escherichia coli ribosomes to be an obligatory intermediate in the formation of the 70S initiation complex. The formation of the 70S initiation complex began with an induction period and was proportional to the concentration of the 30S complex, which rapidly rose to a peak. The entire time course of the sequential pseudo-first-order, second-order reaction was reproduced accurately by the overall rate expression, in which we used rate constants that were determined by carrying out 30S and 70S complex formation separately. By using limiting concentrations of mRNA, we showed that phage MS2 RNA contained no specific signal that enhanced its rate of 30S complex formation with E. coli ribosomes and initiation factors; the pseudo-first-order rate constants obtained with poly(A3C9G1U1), poly(C15G1U4), and poly(G1U3) were 12-45 times higher than that with MS2 RNA. The observation that the rate constants for binding of fMet-tRNA and AcPhe-tRNA with a given synthetic RNA were comparable indicated that the initiator codon is recognized only indirectly through the initiator tRNA.

Anticodon↗
PubMed1979

The effect of protein-energy malnutrition on the development of bones in newborn rats.

Collagen synthesis, 45Ca uptake, and the half-life of 45Ca in mandibles and long bones of rat pups suckled on dams fed 25 or 6% protein diets were determined. Collagen synthesis in both mandibles and long bones was impaired in the malnourished group at an early age. Protein-energy malnutrition appears to affect different developmental processes in these two bones. The principal interference with collagen synthesis in the mandible occurs when bone proline is converted into hydroxyproline. In contrast, proline uptake from the blood for deposit in bone matrix is the step of collagen synthesis mainly affected in long bone. In addition, the critical growth period of mandible was different from that of long bone. The calcium complex fraction (calcium bound to protein plus that in inorganic salts) was the main compartment affected in the malnourished group. However, the efficiency of calcification per milligram of matrix in the calcium complex fraction of the mandible and long bone was approximately the same in the control and malnourished groups, thus suggesting that accumulation of calcium occurs in parallel with the formation of bone matrix regardless of the nutritional conditions. The half-life of 45Ca in the various calcium fractions of both types of bone was 72 hours in both the control and malnourished groups except the calcium complex portion of the long bone of the control group, which was about 100 hours.

Aging↗
PubMed1979

Physical and biochemical changes of the mandible and long bone in protein-energy malnourished newborn rats.

The activities of alkaline and acid phosphatases, the linear dimensions and volumes of mandibles and long bones, and the level of calcitonin in serum of rat pups suckled on dams fed 25 or 6% protein diets were determined. In both mandibles and long bones, alkaline phosphatase activity corresponded to the calcification pattern, and acid phosphatase activity paralleled organic matrix formation. The calcitonin level in blood serum of the malnourished pups differed from that of controls only on day 5. The linear dimensions and volume were consistently more affected in long bones than in mandibles. These results may be explained in terms of the critical growth periods of these bones. In the mandible, the critical growth period appears to occur prenatally, whereas in the long bone it occurs postnatally, when the nutritional stress of this experiment was applied. Long bones were thus generally more affected than mandibles.

Acid Phosphatase↗
PubMed1979

The effect of protein-energy malnutrition on the growth of tooth germs in newborn rats.

The effect of protein-energy malnutrition on the growth of molar and incisor tooth germs was studied. Significant differences were found between control and malnourished groups in the weights and calcium contents of both tooth germs. The data point to the importance of the effect of nutrient deficiency on the critical growth period of an oral structure.

Age Factors↗