Nobuo Matsui

Collagen and alkaline phosphatase gene expression during bone morphogenetic protein (BMP)-induced cartilage and bone differentiation

Endochondral bone formation induced by bone morphogenetic protein (BMP) involves expression of collagen Types I and II and alkaline phosphatase (ALP) genes. Expression of these genes was studied in mice after implantation of BMP. The amount of Type I collagen mRNA increased from Day 3 to Day 7, when mesenchymal cell aggregation was observed. On Day 17, Type I collagen mRNA expression was correlated with an increased number of osteoblasts. Type II collagen mRNA increased from Day 7 and coincided with chondroblast appearance. This increase was suppressed by Day 17, although hypertrophic and degenerative chondrocytes were present. Alkaline phosphatase mRNA increased markedly from Day 7 with the appearance of chondroblasts. The high level of ALP mRNA continued until Day 11, during chondrogenesis. Mineral deposition was first observed roentgenographically on Day 11. Thus, BMP-induced bone formation occurs with the expression of collagen Types I and II and ALP genes.

Anterior discectomy and interbody fusion for lumbar disc herniation. A review of 350 cases.

Based on the follow-up evaluation of 350 patients in whom lumbar disc herniation was treated by anterior discectomy and interbody fusion from 1955 to 1982, 94.3% of the patients obtained bony union and justified the principle of interbody stabilization of the spine. The normalization of the myelographic pattern observed after surgery indicates that sufficient nerve decompression can be obtained by this procedure. The good clinical results may be attributed to the restoration of disc height and to the correction of spinal alignment. The good results observed in long-term follow-up evaluation of 223 patients and the fact that most of the patients resumed their former work after surgery provide further testimony of the value of interbody fusion. The procedure is indicated in young adults, physical laborers with low back pain and sciatica, and patients with spinal instability.

Expression of human placenta alkaline phosphatase in placenta during pregnancy

To clarify the expression of PLAP during the course of pregnancy, the amount of PLAP mRNA and its activity in normal placental villi were measured. Both PLAP and its mRNA were found in placentae of as early as 7 weeks of gestation, and they continued to increase throughout pregnancy. But they showed different patterns of increase. The amount of PLAP mRNA began to increase dramatically around 13th week and probably continued to increase gradually until term. PLAP activity per gram of villi showed a gradual increase from around 13th week and a marked increase was observed after about 20th week. PLAP levels in sera from pregnant women were also measured, and they showed a pattern of increase imilar to that of PLAP activity per gram of villi. The continuous increase in the expression of PLAP throughout pregnancy suggests that PLAP may play a role in feto-maternal metabolism and placental differentiation.

Effect of Estrogen on Prolactin mRNA in the Rat Pituitary

The effect of estrogen on prolactin (PRL) synthesis at a single-cell level was studied by in situ hybridization and immunohistochemistry. Long-term estrogen treatment increased PRL-containing cells from 10-20% of total cell population to 80-90%, as revealed by immunohistochemistry. PRL mRNA containing cells also increased in a similar fashion. Moreover, cytoplasmic PRL mRNA expressed as the number of silver grains per cell increased 4- to 5-fold by estrogen. These results suggest that long-term estrogen treatment causes not only PRL cell proliferation but also an increase in PRL mRNA in a single cell.

Factors related to the recurrent hyperfunction of autografts after total parathyroidectomy in patients with severe secondary hyperparathyroidism

Total parathyroidectomy with autotransplantation has been widely accepted as the appropriate treatment for patients with hyperparathyroidism due to chronic renal failure on long term hemodialysis. However, recurrence has been an enigma and therefore, the factors involved in the recurrence of hyperparathyroidism were studied in 128 patients followed for more than 2 years after surgical treatment. The preoperative serum parathyroid hormone (PTH) concentrations correlated with the total weights of the parathyroid glands. When the original autotransplanted glands were divided into two groups, being diffuse and nodular, the rate of recurrent hyperparathyroidism due to graft hyperfunction was significantly higher in the patients who received nodular glands (24%) than in those who received diffuse glands (8.4%) (P<0.05). To investigate whether PTH synthetic activity is different in diffuse and nodular glands, the amount of PTH mRNA was studied by in situ hybridization. There was no significant difference in the amount of PTH mRNA in the cells from either diffuse or nodular glands. These data suggest that the recurrence of hyperparathyroidism is not due to enhanced PTH synthetic activity of autotransplant grafts but to the abnormal growth rate of the transplanted gland.

Developmental expression of the prolactin gene in the chicken

Steady-state levels of prolactin (PRL) mRNA in the pituitary gland during embryonic development were determined by dot blot analyses to relate the changes with those of pituitary and plasma levels of PRL. Steady-state levels of the 1.38-kb mRNA encoding the PRL prohormone remained low until Day 18 of incubation, increased on Day 19 of incubation, and reached maximum levels on the day of hatch but decreased 1 day after hatch. Changes in both pituitary and plasma concentrations of PRL closely mimicked those changes in PRL mRNA levels. Subsequently, both the levels of the pituitary PRL mRNA and PRL remained unchanged whereas those of plasma PRL increased 7 days after hatch. The results indicate that a progressive expression of PRL gene in the pituitary gland occurs 1-2 days before the hatch and concomitant increases in plasma concentrations of prolactin may be associated with physiologic changes in pulmonary respiration and hatching.

Potentiation of atrial natriuretic peptide‐stimulated cyclic guanosine monophosphate formation by glucocorticoids in cultured rat renal cells

1 The effect of steroid hormones on atrial natriuretic peptide (ANP)‐stimulated cyclic guanosine monophosphate (cyclic GMP) formation was studied in cultured rat renal cells. 2 ANP increased cyclic GMP formation in a dose‐dependent manner, while cyclic AMP was not changed by ANP. 3 Steroid hormones did not affect basal cyclic GMP levels in cultured rat renal cells. 4 Dexamethasone at 10−8m increased ANP (human and rat ANP)‐stimulated cyclic GMP dose‐dependently in cultured rat renal cells. Cortisol, corticosterone and aldosterone at a concentration of 10−7m also potentiated ANP‐stimulated cyclic GMP formation, although triiodothyronine, oestradiol and testosterone were ineffective. Potentiation of ANP action by these steroids seems to parallel glucocorticoid activity. 5 Dexamethasone did not affect cyclic GMP formation stimulated by sodium nitroprusside which stimulates soluble guanylate cyclase in the cytosol. Therefore, the potentiating action of dexamethasone may be mediated through the action on particulate guanylate cyclase at the plasma membrane. 6 It is suggested that the diuretic action of glucocorticoids may, at least in part, be mediated through the potentiating effect of glucocorticoids on cyclic GMP response to ANP.

The ontogeny of growth hormone in the human fetal pituitary.

To examine the ontogeny of growth hormone synthesis and secretion in human fetus, growth hormone messenger ribonucleic acid was measured in 11 pituitaries from fetuses of 16 to 27 weeks of gestation by hybridization of cytosol ribonucleic acid with complementary deoxyribonucleic acid labeled with phosphate 32. Pituitary growth hormone content and serum growth hormone, thyroxine, and cortisol concentrations were assessed by radioimmunoassay. Growth hormone messenger ribonucleic acid content in the fetal pituitary increased from the early midtrimester, reaching a level 15.3 times higher at 27 weeks of gestation than the value at 16 weeks. However, growth hormone content in the pituitary showed no evident change during 16 to 21 weeks of gestation and started to increase after 22 weeks. Serum concentration of growth hormone was variable but always >50 ng/ml, and the maximal level was observed at 20 weeks of gestation (141 ng/ml). Although serum thyroxine concentration in the fetuses showed no correlation with pituitary growth hormone content or serum growth hormone concentration, serum concentration of cortisol was correlated positively with growth hormone content in the fetal pituitary. These results suggest that the maturation of the growth hormone synthesis and secretion system in the fetal pituitary occurs after 22 weeks of gestation and that cortisol may play some role in the ontogenesis of growth hormone.

Poly (adenosine diphosphate-ribose) synthesis in the anterior pituitary of the female rat throughout the estrous cycle: Study of possible relation to cell proliferation and prolactin gene expression

To investigate whether cell proliferation and PRL gene expression in female rat pituitary during estrous cycle were mediated by the poly (ADP)-ribosylation of chromatin proteins, anterior pituitaries at different estrous cycle were obtained from female Wistar rats, and poly (ADP-ribose) synthesis, DNA synthesis, PRL and GH messenger RNAs and PRL content in the pituitary, and serum concentrations of PRL and estradiol were analyzed. From diestrus to proestrus, poly (ADP-ribose) synthesis, the contents of PRL messenger RNA and PRL in the pituitary increased significantly, and decreased at estrus. However, DNA synthesis and serum concentration of PRL showed a significant increase from proestrus to estrus. Serum estradiol concentration increased from diestrus to proestrus. No significant change was observed in the pituitary GH messenger RNA content during estrous cycle. The increase of PRL messenger RNA from diestrus to proestrus was abolished completely by the administration of nicotinamide, an inhibitor of poly (ADP-ribose) synthesis, to rats at diestrus. These results indicate that poly (ADP)-ribosylation of chromatin proteins may play some role in cell proliferation and transcription of PRL gene during rat estrous cycle.

Telescience testbed in human space physiology

The present telescience testbed study was conducted to evaluate the feasibility of physiological experimentation under restricted conditions such as during simulated weightlessness induced by using a water immersion facility, a reduced capacity of laboratory facilities, a delay and desynchronization of communication between investigator and operator, restrictions of different kinds of experiments practiced by only one operator following a limited time line and so on. The three days experiments were carried out following the same protocols. The operators were changed every day, but was the same the first and the third day. The operators were both medical doctors but not all round experts in the physiological experimentation. The experimental objectives were: 1) ECG changes by changing water immersion levels, 2) blood pressure changes, 3) ultrasonic Echo-cardiographic changes, 4) laser Doppler skin blood flowmetry in a finger, 5) blood sampling to examine blood electrolytic and humoral changes. The effectiveness of the testbed experiment was assessed by evaluating the quality of the obtained data and estimating the friendliness of the operation of the telescience to investigators and operators.