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Biomedical subjects

S Saito

Publications and source records attributed to S Saito.

At least 19 recordsLinked to original sources
PubMed1979

Synthesis of procollagen by odontogenic cells of rabbit tooth germ.

Studies were performed to determine whether cultured odontogenic cells from rabbit tooth germ (RP cell) could synthesize dentine-like collagen. When cells were cultured with [14C]proline, 33% of the total incorporated proteins present were collagenous. Cultured RP cells were labeled with [14C]proline in the presence of beta-aminopropionitrile. The resulting fractions, on analysis by CM-cellulose chromatography, contained three radioactive protein peaks, alpha 1(I), [alpha 1(III)]3, alpha 2. From the radioactive measurements, RP cells synthesized a significant amount of type III collagen, comparable to type I collagen. DEAE-cellulose chromatography was used to separate collagen molecules from collagen precursors. The results showed that 60% of total collagen precursor was type III precursor and the remainder was type I precursor. CM-cellulose chromatography of CNBr peptides of collagen from culture medium and cell extract revealed the presence of type I and type III collagen. Thus, the RP cell, which is a diploid cell, is unique in the predominance of type III collagen in culture, differing thereby from the character of collagen in vivo.

Animals↗
PubMed1979

[Endocrine function before and after treatment in patients with anorexia nervosa (author's transl)].

In order to investigate changes in endocrine function, various tests were performed on eleven patients with anorexia nervosa. In two of them, endocrine function before and after treatment was also studied. The responses of plasma LH and FSH to LH-RH were decreased in the patients as were plasma LH-RH, and LH and FSH responses to the oral administration of clomiphene citrate. In more than half of the cases, plasma TSH showed a delayed response to TRH. The basal levels of plasma GH were elevated, and plasma GH responses to hypoglycemia or 1-arginine were lowered in half of the patients. Plasma GH showed a paradoxical rise after glucose load in three out of six cases. Plasma IRI responses to 1-arginine load were decreased in some cases, but plasma IRG responses to 1-arginine were rather excessive. Plasma IRI after glucose load showed low or delayed responses in most of the cases. After the body weight was increased to normal levels by the treatment, pituitary and pancreatic endocrine functions were normalized. These findings indicate that hypothalamic function is primarily impaired in this disease and causes nutritional disorder followed by the dysfunction of some endocrine organs. Such a possibility could be supported by the improvement of endocrine function after body weight has been recovered.

Adolescent↗
PubMed1979

Role of thymectomy in the surgical treatment of myasthenia gravis.

Of the 26 patients with myasthenia gravis undergone thymectomy, 11 cases had either benign or malignant thymoma as judged not only by hitological examination but also by their clinical and operative findings. Age of initial onset ranged from 13 to 64 years old. Fifteen out of 26 (58 per cent) benefited from thymectomy. Duration of the symptom from the onset to the operation and the presence or absence of the thymoma are not related to their outcome. Benign or malignant nature of thymoma should not be determined by histological examination alone but by combined evaluation of clinical and operative findings. Serial studies of serum immunoglobulin levels before and after thymectomy suggested that this disorder could be associated with humoral antibody (IgG). HLA typing of the patients with myasthenia gravis did not indicate the presence of any specific antigens.

Adolescent↗
PubMed1979

Thyroid peroxidase activity in euthyroid and mild hypothyroid patients with Hashimoto's thyroiditis.

Thyroid peroxidase (TPO) activity was measured spectrophotometrically according to Hosoya's guaiacol method. The mean TPO activity in ten patients with Hashimoto's thyroiditis was 19.8 +/- 7.6 (mean +/- SE) in an arbitrary unit, which was not significantly different from the normal value in seven normal thyroid tissues (33.7 +/- 5.4). The ten patients were divided into two groups, euthyroid and mild hypothyroid, on the basis of their basal serum TSH. In the euthyroid group, TPO activity (8.17 +/- 1.3) was significantly less than the normal tissue (p less than 0.01). In the hypothyroid group, TPO activity (27.64 +/- 13.8) was almost similar to the normal tissue. A positive correlation was obtained between TPO activity and serum TSH in ten patients with Hashimoto's thyroiditis (r = 0.85, p less than 0.01). It was concluded that TPO activity is significantly decreased in Hashimoto's thyroiditis even when the thyroid function was still within normal range, but the activity might be restored to normal in hypothyroid patients by the stimulation of elevated TSH.

Adult↗
PubMed1979

Effect of transection on choline acetyltransferase, thyrotropin releasing hormone and substance P in the cat cervical cord.

The effects of a transection on the choline acetyltransferase activity, the thyrotropin releasing hormone and substance P contents in the cat cervical spinal cord have been investigated. Seven days after the hemitransection at the C1 level, the grey matter of the C6-7 levels of the spinal cord were dissected for the biochemical measurements. The choline acetyltransferase activity and the thyrotropin releasing hormone content remained unchanged in any regions in the grey matter following the high cervical transection. On the other hand, the substance P content was decreased by approx. 70% in the ventral horn. These results suggest that the fibers originating the supraspinal structures and terminating in the grey matter of the spinal cord, contain the substance P-releasing fibers, whereas there seems to be little cholinergic or thyrotropin releasing hormone-containing fibers.

Acetyltransferases↗
PubMed1979

Effect of pentobarbital and urethane on the release of hypothalamic somatostatin and pituitary growth hormone.

Hypothalamic somatostatin release was investigated in the rat to elucidate the mechanism of anesthetic action on growth hormone (GH) release from the pituitary. Intraperitoneal injection of sodium pentobarbital (5 mg/100 gm B.W.) significantly elevated serum GH levels and increased hypothalamic somatostatin concentration from basal values of 0.98 +/- 0.01 to 1.21 +/- 0.06 ng/mg wet wt. In contrast, urethane (150 mg/100 gm B.W., IP) administration lowered serum GH levels and hypothalamic somatostatin concentration (0.64 +/- 0.04 ng/mg wet wt.). However, the mean concentration of pancreatic somatostatin showed no change in either case. In rats receiving passive immunization with 0.5 ml rabbit antiserum to somatostatin (SRIF-AS), serum GH levels were significantly increased (67.5 +/- 12.3 ng/ml) and did not differ from those in the group treated with normal rabbit serum (NRS) plus pentobarbital (101.3 +/- 18.5 ng/ml). However, serum GH levels in rats injected with SRIF-AS plus pentobarbital were increased to higher values than in rats given SRIF-AS alone. When urethane was administered to rats after passive immunization with SRIF-AS, urethane-induced suppression of serum GH levels was markedly inhibited (5.5 +/- 2.0 vs. 33.5 +/- 7.5 ng/ml). These results suggest a possibility that the changes in serum GH levels observed with pentobarbital or urethane administration may be induced at least in one part by somatostatin released from the hypothalamus.

Animals↗
PubMed1979

Synthesis of procollagen by dental pulp cells from incisor in vitro.

Fibroblast-like cells were isolated from dental pulp of rabbit incisor, and were shown to synthesize and secrete procollagen. Analysis of the secreted procollagen and their CNBr peptides indicated that the prominent form was type I procollagen. Our results also suggested the presence of type III procollagen as a minor component synthesized by pulp cells in vitro.

Animals↗
PubMed1979

Priming increases the amount of interferon mRNA in poly(rI).poly(rC)-treated L cells.

Priming by mouse interferon pre-treatment resulted in an accumulation of interferon mRNA in poly(rI).poly(rC)-treated L cells, starting early in the period of interferon synthesis. On electrophoresis, the priming activity of an interferon preparation co-migrated with the antiviral activity, which suggests identity of the functional principle(s) for these activities.

Animals↗
PubMed1979

Effects of vasoactive intestinal peptide on glycogenolysis in cultured liver cells.

When isolated rat liver cells were incubated in the presence of vasoactive intestinal peptide at the concentrations ranging from 0.2 microgram to 2 micrograms per ml, glycogenolysis was maximally stimulated within 15 min. However, somatostatin inhibited the liver glycogenolysis. The combined addition to the incubation medium showed that insulin and somatostatin inhibited the stimulated glycogenolysis induced by vasoactive intestinal peptide, while vasoactive intestinal peptide plus secretin showed no additive effect on glycogenolysis, as compared with single the addition of vasoactive intestinal peptide. On the other hand, the additon of glucagon to vasoactive intestinal peptide showed additive effects on glycogenolysis. These results suggest that the receptor site for vasoactive intestinal peptide may be distinguishable from that for glucagon. Extracellular calcium ions were demonstrated to play an important role in the modulation of vasoactive intestinal peptide-induced glycogenolysis. The evidence presented in this paper indicates that glucose metabolism may be partly regulated by the direct action of vasoactive intestinal peptide on hepatocytes, which is referred to as an enterohepatic axis and that the axis is inhibited by insulin and somatostatin.

Animals↗
PubMed1979

Changes in thyroid hormones by treatment with aspirin and prednisolone in subacute thyroiditis with hyperthyroidism.

Thyroid functions were studied in 11 patients with subacute thyroiditis accompanied by signs and symptoms of hyperthyroidism, and were compared with 13 patients with untreated thyrotoxicosis in which serum T4 was elevated to the identical level. Serum T3 was also elevated in subacute thyroiditis but to a significantly lower extent than in thyrotoxicosis. Therefore the ratio of T4/T3 was significantly higher in subacute thyroiditis than in thyrotoxicosis. Although duration of thyroid swelling was shorter in the group treated by prednisolone than by aspirin, the accelerated ESR, thyroid tenderness and fever subsided almost similarly in the two groups. Serum T4 and T3 levels declined more rapidly in treatment with prednisolone compared with aspirin. In patients treated by aspirin initial increase in T3 level occurred transiently with simultaneous decrease in the T4/T3 ratio. These changes suggest the increase in peripheral conversion of T4 to T3. Even in severe cases of subacute thyroiditis associated with hyperthyroidism, aspirin treatment is an effective therapy and there is no recurrence following withdrawal of the medication.

Adult↗