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Biomedical subjects

N Matsui

Publications and source records attributed to N Matsui.

At least 145 records · Page 8Linked to original sources
PubMed1992

Gonadotropin induces expression of c-fos and c-jun genes in rat ovaries.

It has been shown that the expression of protooncogenes, c-fos and c-jun, induced by growth factors and hormones plays important roles in cellular proliferation, tissue differentiation and transcription of certain genes. Since gonadotropin stimulates ovarian steroidogenesis and cellular proliferation, we investigated whether gonadotropin affects the expression of c-fos and c-jun genes in rat ovaries. The expression of mRNA coding side chain cleavage enzyme (P450scc), the rate limiting enzyme in ovarian steroidogenesis was also studied. The effect of gonadotropin was examined in female rats whose gonadotrophs were medically ablated by GnRH agonist (TAP-144-SR). After intravenous administration of pregnant mare's serum gonadotropin (PMSG:30 IU/rat), their ovaries were dissected out at various time intervals and total RNA was extracted. Changes in the levels of c-fos, c-jun and P450scc mRNAs were determined by Northern blot analysis. The levels of c-fos and c-jun mRNAs increased rapidly and transiently with the peak levels at 15 min after PMSG administration. The levels of both mRNAs were decreased by 30 to 60 min. On the other hand, the levels of P450scc mRNA started to increase 60 min after PMSG. These results indicate that gonadotropin-induced increase in the expression of c-fos and c-jun genes may play important roles in mediating the action of gonadotropin on the ovaries.

Actins↗
PubMed1992

Source of prolactin in human follicular fluid.

To analyze whether prolactin (PRL) in human follicular fluid (FF) is synthesized locally or derived from the circulation, PRL concentrations of plasma and FF were determined in the patients after ovarian stimulations. The amounts of PRL messenger ribonucleic acid (mRNA) in the follicular tissues during different menstrual phases were also determined. The FF PRL concentration was correlated positively with plasma PRL and highest estradiol levels during the stimulatory cycle. No PRL mRNA sequence was detected in the RNAs extracted from follicles at any stage in the menstrual cycle, although beta-actin mRNA was detected in all samples. In a comparison with pituitary RNA, the PRL mRNA concentration in ovarian follicular tissues seemed to be 10,000 times less than that in the pituitary. These results suggest that FF PRL may not be synthesized locally, but derived from the pituitary via the circulation through passive diffusion, and thus regulated by estrogen.

Actins↗
PubMed1992

Endocrinological evaluation of ACTH-secreting pituitary microadenomas: their location and alpha-melanocyte stimulating hormone immunoreactivity.

It has been hypothesized by Lamberts and coworkers in their analysis of 15 cases that adrenocorticotropic hormone (ACTH)-secreting pituitary adenomas may be derived from either the anterior lobe or the intermediate lobe. The intermediate lobe type of Cushing's disease is thought to be controlled through a hypothalamic pathway and is characterized by hyperprolactinemia; suppressibility of cortisol with bromocriptine, and lower sensitivity to dexamethasone. The authors investigated the validity of this hypothesis in 125 cases of ACTH-secreting pituitary microadenomas by analyzing the endocrine findings, the locations of the microadenomas, and alpha-melanocyte stimulating hormone (alpha-MSH) immunoreactivity in the adenoma cells. No significant differences in the basal hormone levels, cortisol suppressibility with bromocriptine, sensitivity to dexamethasone, and recurrence rate were observed between patients with the microadenoma adjacent to the posterior lobe (considered typical of the intermediate lobe-derived tumor) or those with the microadenoma located in the anterior lobe. The locations of the microadenoma were not correlated with alpha-MSH immunoreactivity in the adenoma cells. No significant differences in endocrine findings were noticed between adenomas positive or negative for alpha-MSH. Thus, Cushing's disease cannot be simply divided into either the anterior lobe type or the intermediate lobe type by endocrinological evaluation as described by Lamberts, et al.

Adenoma↗
PubMed1992

Antitumor effect of thermosensitive CDDP-liposomes on human osteosarcoma cells in culture.

We have administered cis-diamminedichloroplatinum (II) (CDDP) containing thermosensitive liposome and simultaneous hyperthermia into human osteosarcoma cells (OST) and studied the antitumor effects. Experiments were conducted under the following three different culture conditions as follows, (1) drug treatment alone, (2) hyperthermia after drug treatment, and (3) simultaneous hyperthermia and drug treatment. Antitumor effects were estimated by inhibition of DNA synthesis and decrease in cell growth rates. The antitumor action of simultaneous hyperthermia and drug treatments was the most dominant and synergistic among three experimental conditions. Accumulation of cellular platinum from thermosensitive CDDP-liposomes was markedly enhanced by hyperthermia. Flow cytometric analysis of the cell cycle indicated that CDDP-liposomes only under the simultaneous application of hyperthermia released free CDDP, and evoked cell accumulation in S and G 2/M phase. The results suggested that thermosensitive CDDP-liposomes were not taken up into cells by endocytosis, and released free CDDP into culture media under hyperthermia at 42 degrees C. From these, we have concluded that administration of thermosensitive CDDP-liposomes and simultaneous local hyperthermia could be a promising method for the treatment of osteosarcoma especially in the extremities.

Cisplatin↗
PubMed1991

von Recklinghausen neurofibroma produces neuronal and glial growth-modulating factors.

Two kinds of novel neural trophic factors were currently detected in von Recklinghausen neurofibroma (NF1) extracts. One of the two was a growth factor, neuroblastoma growth factor (Mr less than 5 kDa), which promotes the proliferation of human neuroblastoma cell and survival and neurite-extension of rat cortical neurons, but differently from nerve growth factor (NGF) or NGF-like factors. The other one was a glial growth inhibitor (Mr = 100 kDa), which suppresses the growth of glioma cell lines, astrocytoma, glioblastoma, oligodendroglioma and Schwannoma. These factors do not appear to be previously identified cytokines or growth factors such as interleukins, granulocyte colony-stimulating factor, NGF and fibroblast growth factor. There was also detectable ciliary neurotrophic factor-like activity in the extracts. The primary cause of high contents of these factors in NF1 is not known, but may relate to fundamental mechanisms controlling growth and differentiation of neurons and glias during development of nervous system.

Animals↗
PubMed1991

Molecular cloning and primary structure of rat thyroxine-binding globulin.

Rat thyroxine-binding globulin (TBG) cDNAs were isolated from a rat liver cDNA library by using a human TBG cDNA as a probe. From two overlapping cDNA inserts, an aligned cDNA sequence of 1714 nucleotides was obtained. There was 70% homology with human TBG cDNA over the span of 1526 nucleotides. In order to confirm that the cloned cDNA encodes rat TBG and to localize the NH2-terminal amino acid of the mature molecule, the protein was purified by affinity chromatography and subjected to direct protein microsequencing. The NH2-terminal amino acid sequence was identical with that deduced from the nucleotide sequence. The rat TBG cDNA sequenced consisted of a truncated leader sequence (35 nucleotides), the complete sequence encoding the mature protein (1194 nucleotides) and the 3'-untranslated region (485 nucleotides), containing two polyadenylation signals. It was deduced that rat TBG consists of 398 amino acids (Mr = 44,607), three NH2-terminal residues more than human TBG, with which it shares 76% homology in primary structure. Of the six potential N-glycosylation sites, four are located in conserved positions compared to human TBG. Northern blot analysis of rat liver revealed an approximately 1.8-kilobase TBG mRNA. Its amount increased markedly following thyroidectomy and decreased with thyroxine treatment in a dose-dependent manner.

Amino Acid Sequence↗
PubMed1991

Diuretics modify [Arg8]vasopressin-stimulated cAMP but not atrial natriuretic peptide-stimulated cGMP formation in renal cells.

The present study was undertaken to examine whether sulfonamide-derived diuretics affect [Arg8]vasopressin (AVP)-stimulated or atrial natriuretic peptide (ANP)-stimulated cyclic nucleotide formation in cells cultured from rat or dog kidney. In rat renal cells, all four sulfonamide-derived diuretics examined significantly suppressed 10(-9) M AVP-stimulated cAMP formation at concentrations of 10(-4) and 10(-3) M, while basal cAMP formation was unchanged by the diuretics. When cells were stimulated with 10(-7) M AVP, low ceiling diuretics (indapamide and trichlormethiazide) did not suppress cAMP formation, while high ceiling diuretics (furosemide and azosemide) significantly suppressed cAMP formation at concentrations of 10(-4) and 10(-3) M. The suppressive effect of the diuretics on AVP-stimulated cAMP formation in vitro paralleled the reported diuretic potency of the agents in vivo. In dog renal cells, all four diuretics significantly suppressed 10(-9) M AVP-stimulated cAMP formation at concentrations from 10(-6) to 10(-5) M, while these diuretics did not change basal cAMP levels. High ceiling diuretics suppressed 10(-7) M AVP-stimulated cAMP formation, whereas low ceiling diuretics did not. The difference in effective doses between rats and dogs seems to be consistent with the species difference observed in vivo. None of the diuretics affected basal levels of intracellular cGMP or ANP-stimulated cGMP formation in cultured rat renal cells. In addition to the inhibition of the Na/K/Cl co-transporter, it is suggested that most sulfonamide-derived diuretics act, at least in part, by inhibiting the actions of AVP.

Animals↗
PubMed1991

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.

Amniotic Fluid↗
PubMed1991

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 day's 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.

Aerospace Medicine↗
PubMed1991

Angiotensin-converting enzyme activity as a prognostic factor in acute renal failure.

We evaluated serum angiotensin-converting enzyme (ACE) activity and thyroid function to determine the importance as prognostic factors in acute renal failure (ARF). Among 37 ARF patients, 24 survived (recovered group) and 13 died (lethal group). Both serum thyroxine (T4) level and ACE activity were lower in ARF as a whole group (n = 37) than normal control group (n = 27, p less than 0.01). Both serum T4 level and ACE activity in lethal group (n = 13) were significantly lower than those of the recovered group (n = 24, p less than 0.01). Serum ACE activity but not serum T4 level was significantly related to the prognosis of ARF (p less than 0.02, Mantel-Haenszel analysis). This suggests that lowered serum T4 levels are not a specific indicator of ARF, but lowered ACE activity is significantly related to the prognosis of the patient in ARF. Serum ACE activity seems to be one of several clinically useful prognostic indicators in ARF.

Acute Kidney Injury↗
PubMed1991

Dexamethasone-nonsuppressible cortisol in two cases with aldosterone-producing adenoma.

Forty-one patients with aldosterone-producing adenoma (APA) were subjected to a dexamethasone suppression test (DST) before surgery. Serum cortisol and urinary excretion of 17-hydroxycorticosteroids were suppressed by dexamethasone in 39 patients [DST(+)]. In two patients (cases A and B), they were not suppressed [DST(-)]. Clinical manifestations of the two DST(-) patients were similar to those of DST(+) patients. Hypertension, hypokalemia, high serum aldosterone levels, and suppressed PRA were found in all of the patients. The cut surfaces of the adenomas from all of the patients, including cases A and B, were golden yellow, which is typical of APA. However, atrophies of the adjacent normal tissues were evident exclusively in the two DST(-) patients. After removal of the affected adrenals, the serum cortisol level was suppressed by dexamethasone in one of the DST(-) patients (case B). These findings suggested autonomous cortisol production by APA. To evaluate whether cortisol could be produced from the adenoma tissue, the presence of several steroidogenic enzymes was studied by immunohistochemistry and mRNA analysis in the adenomas and the adjacent nonneoplastic adrenals from the 2 DST(-) and 5 DST(+) patients. Immunohistochemical analysis demonstrated that steroidogenic enzymes were expressed in APA tumor tissues from both DST(-) and DST(+) patients. In both groups, mRNAs coding steroidogenic enzymes were present not only in the nonneoplastic but also in the tumor tissues. Quantitative analysis of the mRNA levels revealed that in the adrenals from DST(+) patients, the mRNAs were more abundant in nonneoplastic tissue than in tumor tissue. However, in those from DST(-) cases, the mRNAs were much more abundant in the tumor tissues than in the nonneoplastic tissues. These results indicate that tumor cells of the two DST(-) patients autonomously synthesized not only aldosterone but also cortisol. The diameters of the tumors from the two DST(-) patients exceeded 3 cm, while those from other DST(+) patients were smaller. In patients with large APA, adrenal insufficiency should be anticipated upon removal of the tumor.

Adenoma↗
PubMed1991

Nucleotide deletion resulting in frameshift as a possible cause of complete thyroxine-binding globulin deficiency in six Japanese families.

Complete T4-binding globulin deficiency (TBG-CD) is inherited in an X-linked fashion. A nucleotide substitution has been shown to cause this hereditary condition in caucasians of French Canadian origin. Heterogeneity in molecular mechanisms for TBG-CD has also been reported. Genomic DNA from a Japanese male exhibiting TBG-CD was subjected to polymerase chain reaction, and the generated DNA fragments were sequenced. A single nucleotide deletion was found in the first base of the codon for amino acid 352 of the common-type TBG molecule. This mutation causes a frameshift in translation and premature termination. Compared with common-type TBG, the mutated polypeptide results in 1) 22 different amino acids on its carboxy-terminus, 2) a 22-amino acid truncation, and 3) the absence of a potential N-linked glycosylation site. These alterations may lead to profound changes in the secondary and tertiary structures of the molecule. To ascertain the presence of this nucleotide deletion in the genomic DNA of affected subjects, a mutated primer was designed which together with the nucleotide deletion produced a new endonuclease restriction site in the polymerase chain reaction fragment. Results revealed the presence of the mutation in genomic DNA of the subject, and his mother was shown to have both mutant and normal alleles. The same mutation was also detected in five other unrelated families carrying TBG-CD. This mutation may be frequent in Japanese subjects with TBG-CD.

Amino Acid Sequence↗
PubMed1991

Immunohistochemical studies on ontogeny of bovine lymphoid tissues.

Developing lymphoid tissues of bovine fetuses ranging from 70 to 270 days of fetal age were examined by histological and immunohistochemical procedures. In the peripheral blood, surface membrane immunoglobulin bearing cells (B-lymphocytes) and sheep red blood cell rosette forming cells (T-lymphocytes) had already appeared by 70 days of fetal age. In the lymph nodes intracytoplasmic IgM positive cells appeared at 90 days of fetal age. The cells positive for IgG appeared at 150 days of fetal age and IgA positive cells appeared at 180 days of fetal age. The spleen contained intracytoplasmic immunoglobulin positive cells at almost the same time as those in the lymph nodes. In the ileocecal region, IgM positive cells and IgG positive cells were present at 180 days of fetal age and IgA positive cells were present at 210 days of fetal age. The tonsils contained IgM positive cells and IgG positive cells at 240 days of fetal age. In the thymus, terminal deoxynucleotidyl transferase positive cells appeared at 90 days of fetal age.

Animals↗
PubMed1991

Suckling stimulates the expression of vasoactive intestinal polypeptide gene in rats.

The effect of suckling on vasoactive intestinal polypeptide (VIP) gene expression in the hypothalami was studied during the postpartum period in rats. Female rats were divided into two groups immediately after delivery. In one group, a mother was housed with 8 pups, and in the other, without any pups. The former group was named S(+) and the latter S(-). On days 0, 3, 6, 9 and 12 after delivery, the mothers were killed by decapitation. Hypothalamic VIP mRNA was measured by RNA dot hybridization. Although the VIP mRNA level showed no significant change after delivery in the S(-) group, VIP mRNA in the S(+) group on days 6, 9 and 12 increased to 1.6, 3.5 and 2.1 times higher than the level observed on day 0, respectively. These results suggest that suckling induces the synthesis of VIP after 6 postpartum days.

Actins↗
PubMed1991

Expression of prolactin gene in incubating hens.

Steady-state levels of the 1.38-kb mRNA encoding the prolactin prohormone, measured by northern and dot blotting using a radioactive cDNA probe, rose 10-fold with concomitant increases in concentrations of prolactin in anterior pituitary and plasma from non-incubating to incubating stages in Gifujidori bantam hens. Daily injections of a low dose of thyrotrophin-releasing hormone (TRH, 0.25 micrograms/kg) for 4 days caused no changes in the concentrations of prolactin of the mRNA, but a high dose (2.5 micrograms/kg) of TRH did induce a significant increase in prolactin mRNA levels compared to saline controls. The results suggest that gene expression for prolactin increases substantially during the incubation period and TRH may contribute, at least in part, to the increase in transcription of prolactin mRNA for prolactin biosynthesis in Gifujidori bantam hens.

Animals↗