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Biomedical subjects

K Higuchi

Publications and source records attributed to K Higuchi.

At least 415 records · Page 23Linked to original sources
PubMed1984

Dexamethasone increases both catecholamines and methionine-enkephalin in cultured bovine adrenal chromaffin cells and human extramedullary pheochromocytoma cells.

The effect of dexamethasone on dispersed cells in primary monolayer culture from bovine adrenal medulla and human extramedullary pheochromocytoma was examined by estimating the level of catecholamines (CAs) and Methionine-enkephalin (Met-enk) in the medium and cells. In cultured bovine adrenal chromaffin cells, dexamethasone caused significant increase in Met-enk levels 18 hours after administration. There was no release of Met-enk and CAs in the medium 10 min after administration, although nicotine did cause a significant release of Met-enk and CAs. A dose response increase in the level of CAs and Met-enk in bovine adrenal chromaffin cells was obtained with doses varying between 0 and 10(-6)M dexamethasone 18 hours after administration. In cultured human extramedullary pheochromocytoma cells, dexamethasone significantly increased the levels of norepinephrine and Met-enk in a dose dependent manner 24 hours after administration. These results suggest that dexamethasone does not act as a secretagogue but may be related to the synthesis of Met-enk and CAs.

Adrenal Medulla↗
PubMed1984

Cataract and other ophthalmic lesions in senescence accelerated mouse (SAM). Morphology and incidence of senescence associated ophthalmic changes in mice.

In a murine model of accelerated senescence (SAM), grading score and incidence in cataract, periophthalmic lesions, opacity and ulcer of the cornea were determined in mice from 4 to 24 months of age. From 4 to 6 months of age, incidence and grading score of these four categories began to increase in both the accelerated senescence prone (SAM) and resistant series with normal aging, and these increases continued with aging. As compared with the resistant series, there was a higher incidence and grading score of the four categories and a higher rate of increase in the prone series. The prone 3 series in particular showed a much higher incidence and grading score on cataract, the rate being 27.5% and 70.6% at 12 and 16 months, respectively. Histologically, the cataract was classified into two types. In one, degeneration of lens fibers, disintegration of lens cortex, and at an advanced stage, liquefaction of the lens cortex and proliferation of the anterior lens epithelial cells occurred. In the other type, lens fibers lost their distinct shapes and a homogenous mass formed at the anterior and posterior superficial cortex. The anterior lens epithelial cells had shrunk. There was an opacity and ulcer of the cornea with keratitis and the corneal epithelium was lost in case of the latter. Periophthalmic lesions included catarrhal changes of the skin of the eyelids and face and blepharitis. There were no lesions specific to each of the prone and resistant series. Thus, SAM should prove to be a suitable murine model for investigation of age-related ophthalmic lesions, including cataract in humans.

Aging↗
PubMed1984

Age-related changes of serum apoprotein SASSAM, apoprotein A-I and low-density lipoprotein levels in senescence accelerated mouse (SAM).

Age-related changes of serum concentration of apo SASSAM, an apoprotein of high density lipoprotein (HDL) which cross-reacts with antiserum against murine senile amyloid fibril protein (ASSAM) were estimated in senescence accelerated mouse (SAM-P) and in senescence resistant series (SAM-R), as a control, using a single radial immunodiffusion technique. Serum concentrations of apo A-I, a major apoprotein of HDL, and low density lipoprotein (LDL) were also measured. In SAM-P (SAM-P/1 and SAM-P/2) with a high incidence of senile systemic amyloidosis, we observed age-associated decreases in serum apo SASSAM levels. The concentrations of apo SASSAM at 16 months of age were below 40% of the concentration at 2 months of age, regardless of the sex. In contrast with SAM-P, we observed no age-associated decrease of serum apo SASSAM levels in SAM-R (SAM-R/1 and SAM-R/2) with a low incidence of amyloidosis. Serum apo SASSAM concentration was higher in SAM-R/1 than in any other strain of mice observed. Serum apo A-I concentration was highly and significantly correlated with the serum concentration of apo SASSAM and decreased with advancing age in SAM-P but not in SAM-R. Age-related changes of LDL were not observed in any strain, but the concentration was lower in the females. In old SAM-P (16 months' old), the concentration of apo SASSAM decreased to one-third of that in the young SAM-P (4 months' old) and the serum concentrations of albumin and total protein did not decrease, compared with those in the young mice. All these findings taken together suggest that abnormality of metabolism in apo SASSAM, putative precursor of ASSAM, might occur in SAM-P.

Aging↗
PubMed1984

Grading score system: a method for evaluation of the degree of senescence in senescence accelerated mouse (SAM).

For evaluation of the degree of senescence in SAM-P, accelerated senescence prone mouse, formerly called SAM or prone series or P-series, consisting of SAM-P/1, SAM-P/2, SAM-P/3 and SAM-P/4 corresponding to P-1, P-2, P-3 and P-4 series, respectively, in the previous reports, and in SAM-R, accelerated senescence resistant mouse, formerly called resistant series or R-series, consisting of SAM-R/1, SAM-R/2 and SAM-R/3 corresponding to R-1, R-2 and R-3 series, respectively, in the previous reports, the grading score system was adopted. The items to be examined in this system include 11 categories selected from the clinical signs and gross lesions considered to be associated with the aging process. The degree of the senescence in each category was graded from 0 to 4 according to the detailed criteria devised in our laboratory. After 8 months of age each mouse was examined every 4 months, and some of the mice were examined after 2 months of age. In almost all categories, the grading score and incidence began to increase from 4 or 6 months of age and continued to increase with advancing age in both SAM-P and SAM-R. The increase, however, was more marked in SAM-P than in SAM-R. The slow but steady increase in the SAM-R levelled out at 24 months of age and was comparable to that at 12 months of age in SAM-P. In both SAM-P/1 at 8 months of age and SAM-R/2 at 12 months of age, there was a significant reverse correlation between total score of this grading score system and length of residual life after examination. Systematic and extensive studies using the grading score system showed that if the validity of the system is, based on "irreversibility" and "universality" of the changes in each category with advancing age, most categories are valid for evaluation of the degree of senescence. This grading score system is a unique, useful and convenient method for evaluation of the degree of senescence in mice.

Aging↗
PubMed1984

Prolactin has a direct effect on adrenal androgen secretion.

The role of PRL in the secretion of androgens by the adrenal glands was investigated in vivo and in vitro. In women with hyperprolactinemia whose pituitary-adrenal function was normal, there was significant correlation between serum PRL and dehydroepiandrosterone sulfate [(DHEA-S) gamma = 0.48, P less than 0.05, n = 34] and DHEA (gamma = 0.50, P less than 0.05, n = 34), but not with androstenedione. Long term administration of sulpiride to normal women increased both serum PRL and DHEA-S, whereas acute elevation of PRL after a single iv dose of domperidone had no influence on the serum DHEA-S levels. Monolayer cultures of human adrenal cells were used in order to study the direct effect of PRL on adrenal androgen secretion. The daily secretion of DHEA-S, DHEA, androstenedione, and cortisol was determined. In the absence of ACTH, PRL had no effect on steroid secretion in a 7-day culture period. In the presence of ACTH, there was a daily increase in the secretion of steroids. PRL, when added in combination with ACTH, potentiated the effect of ACTH on DHEA-S and DHEA but not on androstenedione and cortisol secretion on the seventh day in culture. These results indicate that PRL has a direct synergistic effect with ACTH on adrenal cells to increase adrenal androgen release. Increases in DHEA-S and DHEA but not androstenedione in vitro and correlation between serum PRL and DHEA-S and DHEA but not androstenedione in women with hyperprolactinemia suggest that the synergistic effect of PRL on adrenal androgen secretion may result from partial inhibition of adrenal 3 beta-hydroxysteroid dehydrogenase.

Adrenal Glands↗
PubMed1984

Protein synthesis in dorsal, ventral, animal and vegetal half-embryos of Xenopus laevis isolated at the 8-cell stage.

Dorsal, ventral, animal and vegetal half-embryos of Xenopus laevis were isolated at the 8-cell stage, and their synthesis of protein examined during 12 h of culture. The kinetics of the uptake and incorporation of [35S]-methionine did not differ greatly among the four kinds of half-embryos. Two-dimensional gel electrophoreses showed that there were no detectable differences in the pattern of protein synthesis for the four types of half-embryos, at least during the first 6 h of culture which covered the period from the cleavage to late blastula stage. The patterns, however, changed greatly, especially between those of the animal and vegetal half-embryos, during the latter 6 h of culture which covered the period from the early gastrula to early neurula stage. These results are evidence that equal qualitative and quantitative maternal mRNA-dependent protein synthesis takes place in the four types of embryonic regions, including the vegetal half-embryos, although later in the post-blastular stages, syntheses of region-specific proteins start that are dependent on new genome expression.

Animals↗
PubMed1984

Glucocorticoid receptors in cultured skin fibroblasts of normal and adrenocorticoid disorders.

Glucocorticoid receptors (GR) in cultured fibroblasts obtained by forearm skin biopsy were characterized and GR in patients with hyper- and hypo-cortisolism were compared. Scatchard analysis of specific whole cell [3H]-dexamethasone binding showed a single class of high affinity receptors with a mean (+/- SD) binding capacity (R0) of 126,800 +/- 21,600 sites/cell and mean (+/- SD) apparent dissociation constant (Kd) of 2.9 +/- 0.4 nM in 6 normal subjects. Competition study of various steroids revealed that glucocorticoids were the most potent competitors. The order of the strength of competition was dexamethasone greater than betamethasone greater than prednisolone greater than hydrocortisone. Sucrose density gradient analysis revealed a specific 8.6 S binding peak in cytosol and 3.6 S in nuclear extracts. Dexamethasone showed the dose-dependent suppressive effect on thymidine incorporation. An inverse linear correlation between CI50 and % inhibition of thymidine incorporation by glucocorticoids was observed. There were no significant differences in parameters of whole cell GR among healthy controls, Cushing's disease (n = 4, R0 = 131,225 +/- 29,950/cell, Kd = 3.1 +/- 0.6 nM) and Addison's disease (n = 2, R0 = 131,600 +/- 25,600/cell, Kd = 3.2 +/- 0.2 nM). In one additional patient of hypercortisolism without clinical symptoms of Cushing's disease, R0 (144,000 +/- 12,960) was the same as control, but Kd (5.0 +/- 1.2 nM) was higher than the control.

Addison Disease↗
PubMed1984

Hypothalamic function in women during the first month post-partum.

Plasma LRH-immunoreactive substance in puerperal women was very low on days 5 and 10 post-partum and significantly increased between days 10 and 20 post-partum, but remained at a similar level on day 30 post-partum, which was significantly lower than that in eumenorrhoeic women on day 8 or 9 of the normal cycle. Although LRH administration did not significantly increase serum FSH on day 11 post-partum, daily injections of LRH from days 5 through 10 post-partum caused a significantly increased secretion of FSH on day 11 post-partum, both basally and in response to LRH. No significant difference was observed in serum oestradiol and Prl levels on day 11 post-partum between the two groups of women with and without LRH pre-treatment. It is concluded that the amount of hypothalamic LRH secretion may be small during the first month post-partum, and low basal FSH and unresponsiveness of the pituitary to LRH observed in the early puerperium may result from hypothalamic hypofunction.

Estradiol↗
PubMed1984

[Recovery of gonadotropin-secreting function of the pituitary in the puerperal women with eclampsia].

Recovery of gonadotropin-secreting function of the pituitary has been studied in 4 puerperal women with episodes of eclampsia during the last pregnancy, delivery and/or the first 24 hours after delivery. On day 20 postpartum, hypertension, edema and proteinuria were improved in all the puerperal women. Serum FSH and LH responses to LH-RH on day 20 postpartum in 3 puerperal women with less than 6 eclamptic attacks during pregnancy or delivery were at a comparable level to those on day 20 postpartum in 4 puerperal women with premature labor between 31 and 33 weeks' gestation and in 9 normal puerperal women. Serum FSH response to LH-RH on day 20 postpartum in a puerperal woman with 10 eclamptic attacks during pregnancy and the first 24 hours after delivery was lower than those in 4 puerperal women with premature labor and in 9 normal puerperal women. In the puerperal woman with 10 eclamptic attacks, the lowered FSH response to LH-RH on day 20 postpartum was apparently improved on day 55 postpartum. However, the FSH response to LH-RH on day 55 postpartum was still lower in the puerperal woman with 10 eclamptic attacks than in 7 normal puerperal women. These results indicate that many eclamptic attacks during pregnancy, delivery and/or the first 24 hours after delivery may cause perturbation to some extent in recovery of FSH-secreting function of the pituitary during the puerperium.

Adult↗
PubMed1984

[Hypothalamic-pituitary function in women after abortion or premature labor].

Hypothalamic function during pregnancy and hypothalamic-pituitary function during the first month after abortion or premature labor have been studied. The plasma LH-RH level in pregnant women was significantly lower between 18 and 23 weeks' gestation than that in eumenorrheic women on day 8 or 9 of the normal cycle, and thereafter decreased until term. Serum FSH showed normal response to LH-RH on day 10 after pregnancy termination between 5 and 23 weeks' gestation, but no FSH response to LH-RH was found on day 10 after premature labor at 33 weeks' gestation. Serum FSH responded normally to LH-RH on day 30 after pregnancy termination at 18 weeks' gestation, but serum FSH responded excessively to LH-RH on day 30 after premature labor at 30 weeks' gestation. The positive feedback effect of estrogen on LH release was not operative on day 30 after pregnancy termination beyond 18 weeks' gestation, though it was operative on day 30 after pregnancy termination between 6 and 11 weeks' gestation. These results indicate that the duration of pregnancy has an influence on the recovery of hypothalamic-pituitary function after pregnancy termination and that the recovery of hypothalamic-pituitary function during the first month after premature labor beyond 30 weeks' gestation is similar to that after normal labor.

Abortion, Induced↗
PubMed1983

Isolation and characterization of senile amyloid--related antigenic substance (SASSAM) from mouse serum. Apo SASSAM is a low molecular weight apoprotein of high density lipoprotein.

Sera obtained from senescence-accelerated mouse (SAM) and normal mice contained a substance that reacted with antiserum raised against ASSAM, a novel senile amyloid fibril protein isolated from the liver of SAM. This physiological substance, termed "SASSAM" (serum ASSAM-related antigenic substance), migrated to the albumin/prealbumin region in immunoelectrophoresis and the precipitation line formed with anti-ASSAM antiserum was stained positively with both Amide Black 10 B and Oil Red O/Fat Red 7B solutions, thereby suggesting that SASSAM is an alpha lipoprotein. Using Sephadex G-200 gel chromatography, SASSAM was eluted as a high mol wt form of approximately 200,000 daltons. Fractionation of lipoprotein from normal mouse serum by preparative ultra-centrifugation disclosed that SASSAM was found mainly in high density lipoprotein, HDL (the density is between 1.063 and 1.21 g/cm3). The largest amount of SASSAM was found in the HDL2 fraction (the density is between 1.063 and 1.125) and in this fraction SAA was not detected. Furthermore, ASSAM immunoreactivity appeared in the low mol wt proteins (below 10,000 daltons) of apo HDL separated in the buffer containing 8 M urea through Sephadex G-200. In 8 M urea sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), the major components of apolipoproteins in this position, possibly corresponding to apo C proteins, have the same molecular weight, 5,200 daltons, as ASSAM and this component was labeled by anti-ASSAM antiserum after transfer to nitrocellulose paper.

Aging↗
PubMed1983

Reproductive function following advanced ovulation induced by synthetic luteinizing hormone-releasing hormone in rats.

Reproductive function following advanced ovulation induced by a single injection of 1 microgram synthetic luteinizing hormone-releasing hormone (LH-RH) has been studied in rats. While advanced ovulation induced by an injection of the agent on the day of proestrus was followed by pregnancies occurring as frequently as those in spontaneous ovulation group, incidences of mating behavior, fertilization, and pregnancy were considerably reduced in the advanced ovulation group when induced by an injection of synthetic LH-RH during the early period of diestrus 2. The mean volume of primary oocytes of the three largest follicles at 1.00 h on the day of diestrus 2 was significantly smaller than that at 1.00 h on the day of proestrus. However, shortly before ovulation, the mean volume of secondary oocytes in the preovulatory follicles from rats treated with synthetic LH-RH at 1.00 h on the day of diestrus 2 was approximately the same as that in the preovulatory follicles from rats treated with the agent at 1.00 h on the day of proestrus. Shortly after ovulation the number of mitotic cumulus cells around the oviductal ova was significantly greater in advanced ovulation group induced by synthetic LH-RH injection during the early period of diestrus 2 than in spontaneous ovulation group. Furthermore, when examined 13 h after ovulation, the layers of cumulus cells were thicker, and cumulus cells were more tightly arranged around the ova in the advanced ovulation group induced by injection of synthetic LH-RH during the early period of diestrus 2 than those in the group with with spontaneous ovulation. These results suggest that the cumulus-oocyte complex from advanced ovulation group induced by injection of synthetic LH-RH in the early period of diestrus 2 is less potent in fertilizability than that from spontaneous ovulation group, leading to a reduction in the rate of subsequent pregnancy.

Animals↗
PubMed1983

Systemic senile amyloid in senescence-accelerated mice. A unique fibril protein demonstrated in tissues from various organs by the unlabeled immunoperoxidase method.

Tissue sections of senescence-accelerated mice (SAM) and of mice with normal aging characteristics (R series) were studied using a peroxidase-antiperoxidase (PAP) method with specific antisera against a unique amyloid fibril protein (AS/SAM) and against murine protein AA. Anti-AS/SAM antisera reacted with amyloid tissues of SAM and aged R series mice but not with normal tissues or amyloid tissues containing protein AA. Reactivity of this and serum could be abrogated by absorption with purified AS/SAM. Amyloid deposits in liver, kidney, spleen, gastrointestinal tract, lung, heart, gonads, pancreas, salivary glands, adrenal, thyroid, skin epineurium, and blood vessels were positive for AS/SAM in both the SAM and R series. Brain and bone medulla, however, were not stained. The amyloid deposited in gonads, papillary layer of dermis, and epineurium was exclusively AS/SAM. The amyloid observed in most of the P-1 series mice was AS/SAM. In the P-2 series and R series, protein AA frequently coexisted with AS/SAM as demonstrated using a double staining method. Each amyloid localized preferentially in the liver, spleen, and gastrointestinal tract.

Aging↗