The effects of sarpogrelate on cardiomyocyte hypertrophy

Sarpogrelate was developed as an antiplatelet agent antagonizing 5-hydroxytryptamine (5-HT) receptors. It had been reported that 5-HT receptors were expressed in cardiovascular system, and that sarpogrelate had antihypertrophic effects in vascular smooth muscle cells. Cardiac hypertrophy is a major problem in cardiac diseases, so the present study was designed to elucidate the effects of sarpogrelate on cardiac hypertrophy. Cultured rat cardiomyocytes (MCs) and cardiac nonmyocytes (NMCs) were prepared by Percoll gradient and adhesion method and MCs were incubated with (MCs/NMCs) or without NMCs. As an index of protein synthesis of MCs, [3H]-leucine uptake into MCs and MCs/NMCs was measured. Sarpogrelate decreased [3H]-leucine uptake into MCs (maximum 62.6+/-20.6% of control at 10(-4)M, p<0.05 vs. control). Sarpogrelate also significantly attenuated angiotensin-II- and endothelin-1-induced [3H]-leucine uptake. These results indicated that sarpogrelate might have antihypertrophic effects and could be a useful aid for cardiovascular disease.

Possible involvement of endothelin-1 in cardioprotective effects of benidipine

Benidipine hydrochloride has been developed as an antagonist for the L-type calcium channel and is used as an anti-hypertensive drug. But recent studies have reported that benidipine exerts not only antihypertensive actions but also anti-hypertrophic actions on cardiac muscles. Endothelin-1 (ET-1), one of the endogenous pathological humoral factors of cardiovascular diseases such as hypertension and heart failure, has a strong vasoconstrictive action and could induce hypertension and cardiac hypertrophy. So, it is a matter of great interest whether or not calcium antagonists can decrease cardiac hypertrophy induced by the pathological vasoactive substances such as ET-1. Thus, the present study was designed to elucidate the effects of benidipine on cardiac hypertrophy, and particularly on the interaction with ET-1, using neonatal rat cardiac myocytes (MCs) and cardiac non-myocytes (NMCs) culture systems. Cells were cultured with or without ET-1, benidipine, and nifedipine and the effects of calcium antagonists on cardiac hypertrophy were evaluated by incorporations of [3H]-leucine and [3H]-thymidine into MCs and/or NMCs. Benidipine significantly decreased the ET-1-induced increase of [3H]-leucine and [3H]-thymidine uptake into cardiac MCs and NMCs, whereas no significant effects of nifedipine were observed. Furthermore, benidipine (10(-8)M) attenuated ET-1 secretions from NMCs. In summary, benidipine at least partially decreased the cardiac hypertrophy induced by paracrine mechanisms through its attenuation of ET-1 secretions from NMCs. Benidipine could thus be a useful tool for preventing cardiac hypertrophy due to hypertension.

Characterization of bone morphogenetic protein-6 signaling pathways in osteoblast differentiation

Bone morphogenetic protein (BMP)-6 is a member of the transforming growth factor (TGF)-(β) superfamily, and is most similar to BMP-5, osteogenic protein (OP)-1/BMP-7, and OP-2/BMP-8. In the present study, we characterized the endogenous BMP-6 signaling pathway during osteoblast differentiation. BMP-6 strongly induced alkaline phosphatase (ALP) activity in cells of osteoblast lineage, including C2C12 cells, MC3T3-E1 cells, and ROB-C26 cells. The profile of binding of BMP-6 to type I and type II receptors was similar to that of OP-1/BMP-7 in C2C12 cells and MC3T3-E1 cells; BMP-6 strongly bound to activin receptor-like kinase (ALK)-2 (also termed ActR-I), together with type II receptors, i.e. BMP type II receptor (BMPR-II) and activin type II receptor (ActR-II). In addition, BMP-6 weakly bound to BMPR-IA (ALK-3), to which BMP-2 also bound. In contrast, binding of BMP-6 to BMPR-IB (ALK-6), and less efficiently to ALK-2 and BMPR-IA, together with BMPR-II was detected in ROB-C26 cells. Intracellular signalling was further studied using C2C12 and MC3T3-E1 cells. Among the receptor-regulated Smads activated by BMP receptors, BMP-6 strongly induced phosphorylation and nuclear accumulation of Smad5, and less efficiently those of Smad1. However, Smad8 was constitutively phosphorylated, and no further phosphorylation or nuclear accumulation of Smad8 by BMP-6 was observed. These findings indicate that in the process of differentiation to osteoblasts, BMP-6 binds to ALK-2 as well as other type I receptors, and transduces signals mainly through Smad5 and possibly through Smad1.

A pharmacokinetic model of intravitreal delivery of ganciclovir

A pharmacokinetic model of intravitreal drug delivery was developed for describing the elimination and distribution of ganciclovir in the eye following intravitreous polymeric delivery. The model was based on Fick's second law of diffusion and assumed a cylindrical vitreous body. The model parameters such as the diffusion coefficient and the partition coefficient of the drug in the vitreous body and its surrounding tissues were determined from in vitro experiments using rabbit tissues. The time course of in vivo mean concentration of ganciclovir in the rabbit vitreous body agreed well with the profile calculated from the present pharmacokinetic model for both membrane-controlled polymeric devices and biodegradable rod-matrix systems. The clinical vitreous concentration following implantation of the membrane-controlled delivery system was the same order of magnitude but approximately four times lower than that predicted from the present model. This may indicate the metabolism of ganciclovir and/or the facilitated transport across the retina/choroid membrane in the human eye.

Effect of ultrasound application on skin metabolism of prednisolone 21-acetate

PURPOSE

The effect of ultrasound on skin penetration and metabolism of prednisolone (PN) and prednisolone 21-acetate (PNA) was investigated in the hairless mouse skin in vitro.

METHODS

The abdominal skin excised freshly was pretreated under different ultrasound intensities (4.32, 2.88, and 1.50 W/cm2) for 10, 30, and 60 min. The penetration/metabolism rate of PNA and its metabolite (PN) was then measured using a side-by-side diffusion cell.

RESULTS

The skin penetration of PN was enhanced by the ultrasound pretreatment. This enhancement was attributed to the decrease in the stratum corneum barrier capacity by ultrasound energy. The steady-state appearance rate of PN following the skin bioconversion of PNA decreased appreciably with increasing the product of the duration of pretreatment (Dp, min) and the intensity of ultrasound applied (Iu, W/cm2). When the product value was less than 40 W/cm2 . min, the steady-state appearance rate of the PN hardly increased in spite of the penetration enhancement of PNA.

CONCLUSIONS

These findings indicated a possible deactivation of the skin enzymes by ultrasound energy.

Urocortin, a newly identified corticotropin-releasing factor-related mammalian peptide, stimulates atrial natriuretic peptide and brain natriuretic peptide secretions from neonatal rat cardiomyocytes

The effect of urocortin (UCN), a recently characterized mammalian member of corticotropin-releasing factor (CRF)-related peptide and a putative endogenous ligand for CRF type 2 beta receptor in the regulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release, was investigated using cultured neonatal rat cardiomyocytes. Treatment with UCN (10(-10)-10(-6)M) resulted in significant increase in ANP and BNP secretions, and the effect of UCN on ANP and BNP secretions was more potent than that of CRF on an equimolar basis. The effect of UCN (10(-7)M) was completely blocked by alpha-helical CRF (9-41), a specific CRF type 2 receptor antagonist. The effect of UCN (10(-7)M) was not only blunted by cAMP-dependent protein kinase A (PKA) inhibitor, H-89 (10(-5)M), but also diltiazem (10(-7)M), a voltage-dependent Ca2+ channel blocker. Further, UCN stimulated cAMP production in cardiomyocytes. Also, UCN (10(-7)M) itself stimulated [3H]leucine uptake into neonatal rat cardiomyocytes and potentiated endothelin-1-induced increase of [3H]leucine uptake. These results suggest that activation of CRF type 2 receptor, especially type 2 beta receptor, with UCN induces ANP and BNP secretions, at least in part, via PKA pathway during cardiac hypertrophy.

Oxidative stress suppresses the endothelial secretion of endothelin

To address endothelial function on vascular walls exposed to oxidative stress, we investigated the effect of oxidative stress on the secretion of endothelin-1 (ET-1) from cultured bovine carotid artery endothelial cells (BAECs). Concentrations of ET-1 in the media were measured by a specific radioimmunoassay and ET-1 mRNA expression was estimated by Northern blot analysis. Treatment of BAECs with 0.5-2.0 mM H2O2 for 3 h suppressed both ET-1 secretion and ET-1 mRNA expression in a dose-dependent manner compared to control. Attenuation of ET-1 mRNA expression by H2O2 was revealed to take place at the transcriptional level. The addition of NG-nitro-L-arginine-methyl ester (L-NAME) 10 microns, a specific nitric oxide synthase inhibitor, had no effect on H2O2-induced suppression of ET-1 mRNA expression. Suppression of ET secretion under oxidative stress observed in the present study is proposed to be a compensatory mechanism of endothelial cells to inhibit vasoconstriction and proliferation during oxidative stress.

Lingual thyroid presenting as acquired hypothyroidism in the adulthood

There are numerous reported cases of lingual thyroid with an obvious prevalence in pediatric age. Such ectopic thyroid glands are probably quantitatively deficient and thyroid function may be low or at a low normal level. Apparently, most cases of ectopic thyroid tissue develop congenital hypothyroidism, the so-called cretinism. In this report, we describe a very rare adult male case of lingual thyroid who developed hypothyroidism in adulthood; the anomaly remained undiscovered, being without local common symptoms, and permitted a normal life.

[Delivery of macromolecular drugs to the vitreous and its peripheral tissues]

We evaluated the release behavior of FITC-dextran with an average molecular weight of 4,400(FD4), as a model peptide drug, from poly(DL-lactic acid) (PLA) implant. The drug level in the vitreous and its peripheral tissues were measured following the implantation in the rabbit vitreous. The release profile of FD4 from the PLA implant was biphasic; a fraction of the drug molecules incorporated in the polymer implant was swiftly released; then slowly or even negligibly for a certain period of time and finally complete bursting release probably due to bulk erosion of the polymer. The time-course of drug concentration in the vitreous and aqueous humor after implantation showed a constant level for 14 days and then parabola, where the highest concentration appeared around 28 days. The drug concentrations in the retina/ choroid was maintained a constant level for 28 days. After an injection of FD4 in the rabbit vitreous, the drug concentration in those tissues approximately decreased mono-exponentially. These findings suggest that the present implant could be a useful carrier for delivery of macromolecular drugs to the vitreous and its peripheral tissues.

Intravitreous delivery of dexamethasone sodium m-sulfobenzoate from poly(DL-lactic acid) implants

Biodegradable intravitreal rod-shaped implants containing dexamethasone sodium m-sulfobenzoate (DMSB) were prepared from blends of poly(DL-lactic acid) (PLA) with number-average molecular weight 2000 (PLA2000) and 4000 (PLA4000). The effect of the fraction of PLA2000 on the release of DMSB from the implant was investigated after implantation in the vitreous body of rabbit eyes. After the initial burst, the drug was released slowly from the blended PLA implants with a PLA2000 fraction of below 30 wt% in normal eyes within a period of 28 d. For the implants with a higher PLA2000 fraction of over 50 wt%, the drug was released following approximately first order kinetics. In the vitrectomized eyes, the release of DMSB from the PLA2000/PLA4000 (5/5) implant was 2.5 times more rapid than in normal eyes, and the clearance of drug was also appreciably accelerated as compared with that in normal eyes.

Polymer blend implant for ocular delivery of fluorometholone

Ocular implants containing fluorometholone (FLM) were prepared using blends of poly (DL-lactic acid) (PLA) and polyvinyl pyrrolidone (PVP). The effect of the fraction of PVP content on the release of FLM from the implant was investigated in vitro. The drug was released from the device by approximately following first order kinetics within the period of 40 d. The release rate gradually increased with an increase in the PVP content. The in vivo study after implantation in the anterior chamber of rabbit eyes indicated that the PLA-PVP implant showed a good correlation between the in vitro and in vivo release of FLM. The present polymer blend implant demonstrated a constant level of FLM in the aqueous humor for one month.

Characterization of skin permeation of vitamin C: theoretical analysis of penetration profiles and differential scanning calorimetry study

A mechanism for the relatively high permeability of vitamin C in relation to the change in the protein domain of the stratum corneum has been proposed. Firstly, the skin permeation characteristics of vitamin C (l-[1-14C]-ascorbic acid) using whole skin and stripped skin of the hairless mouse were investigated. By employing a double layer model, physicochemical properties such as diffusivity and solubility of vitamin C in each skin layer, stratum corneum and viable skin were determined. Then, the high skin permeation rate of vitamin C was characterized. A differential scanning calorimetry, (DSC), study was employed to investigate the effect of vitamin C on the stratum corneum, a major diffusion barrier for the skin transport of the compound. Vitamin C was found to permeate rapidly through the skin, in spite of its low lipophilicity. The diffusivity determined from the lag-time was approximately 1000 times higher in the stripped skin, compared with whole skin. There is a dramatic increase (10-fold) in the permeation rate in stripped skin indicating the major barrier presented by the stratum corneum to the skin permeation of vitamin C. The DSC profile showed four very distinctive transitions near 100, 128, 135 and 145 degrees C which are associated with protein transitions. Comparing normal skin, the peaks are sharpened and there are additional phase transitions above 90 degrees C. An increase in sharpness reflects an increase in the hydration state of the sample, as hydrogen bonds between H2) molecules and other hydrogen donating chemicals of skin components become major chemical bonds in hydrated samples. The higher permeation rate of vitamin C observed may be due to its enhancing effect on the hydration capacity of skin and solubilizing action on the protein domain of the stratum corneum.

Binding of prednisolone and its ester prodrugs in the skin

PURPOSE

Skin binding of prednisolone and its esters was investigated in the hairless mouse skin in vitro.

METHODS

The distribution of the amount of drugs bound in the skin was determined by a skin slicing technique. The model drugs used were prednisolone (PN, M.W. 360) and its esters, senesyonate (PN-C5, M.W. 442), geranate (PN-C10, M.W. 510), farnesylate (PN-C15, M.W. 578), and geranylgeranate (PN-C20, M.W. 646).

RESULTS

The distribution of bound drug was nonhomogeneous in the skin; the concentration of PN-C10 and PN-C15 in the skin increased gradually with the distance from the skin surface. The parent drug, PN, however, was hardly bound in the viable skin.

CONCLUSIONS

These findings suggest that the prodrugs of prednisolone may prolong the dermal retention of the parent drug and minimize to delivery into the systemic circulation of the prodrug and metabolite.

Unexplained increase in serum corticosteroid-binding globulin levels in a patient with chronic thyroiditis, pituitary adenoma and empty sella

Unexplained high serum corticosteroid-binding globulin (CBG) concentrations (mean +/- SD, 74.1 +/- 12.1 micrograms/dl; normal women, 32.5 +/- 5.6 micrograms/dl) were found in an unmarried women who was not pregnant or taking exogenous estrogens. She was also found to suffer from subclinical chronic thyroiditis, pituitary adenoma and empty sella. The increased serum CBG concentrations in this patient were not due to any of the factors known to increase CBG. Consistently high basal serum GH levels and unusual GH responses to GH-releasing factor (GRF) and L-dopa were also noted.

Stimulation by corticotropin-releasing factor of atrial natriuretic peptide and brain natriuretic peptide secretions from cultured neonatal rat cardiomyocytes

The new functional role of corticotropin-releasing factor (CRF) in the regulation of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) release was investigated using cultured neonatal rat cardiomyocytes. Treatment with CRF (10(-10)-10(-6) M) resulted in dose- and time-dependent increase in ANP and BNP secretion, up to 2.5-fold and 1.8-fold above control values, respectively. The effect was significant at 6 hr and persisted for at least 36 hr. The effect of CRF (10(-7) M) was partially blocked by alpha-helical CRF(9-41) (10(-7) M), a specific CRF receptor antagonist. The effect of CRF (10(-7) M) was not only blunted by cAMP-dependent protein kinase A (PKA) inhibitor, H-89 (10(-5) M), but also by protein kinase C inhibitors, H-7 (50 microM) and Calphostin C (10(-6) M). H-7 (50 microM) and Calphostin C (10(-6) M) alone lowered basal ANP and BNP levels. Furthermore, CRF (10(-7) M) stimulates protein synthesis up to 1.2-fold. These results indicate that CRF stimulates ANP and BNP secretions through the CRF receptor and, at least in part, via PKA activation during cardiac hypertrophy.

Evaluation for intrinsic skin permeation of unstable compounds

An evaluation method is proposed for the intrinsic skin permeation rate of unstable compounds. Vitamin C and vitamin E were used as the model compounds. The degradation of vitamin C and E in the solutions followed first-order kinetics with degradation constants of 0.26 h-1 and 0.014 h-1, respectively. The apparent skin permeation profiles of vitamin C and E in vitro, approximated by a nonlinear profile of the polynomial regression method, was corrected for intrinsic permeation rate considering first-order degradation in the receptor solution. The intrinsic profiles evaluated agreed well with the ones determined from radio-labelled compounds, indicating the feasibility of the present analysis.

Williams syndrome associated with chronic renal failure and various endocrinological abnormalities

A 31-year-old man who had been under regular hemodialysis for 6 months was diagnosed as Williams syndrome (WS) by fluorescence in situ hybridization (FISH) chromosomal analysis. The association of WS and chronic renal failure (CRF) is only rarely encountered. Endocrinological examinations revealed hypergonadotropic hypogonadism. Prolonged and exaggerated responses of adrenocorticotropin (ACTH) to insulin-induced hypoglycemia and corticotropin releasing hormone (CRH) were also noted. While most of the endocrinological abnormalities observed in this patient could be attributed to altered endocrine circumstances in CRF, some findings stand in contrast. Furthermore, the testicular biopsy specimen showed severe hypospermatogenesis. Endocrine disorders observed in this patient may be at least in part, responsible for various clinical features underlying WS.

47 XXY/46 XY mosaic Klinefelter's syndrome presenting with multiple endocrine abnormalities

We report here a rare case of 47 XXY/46 XY mosaic Klinefelter's syndrome associated with multiple endocrine disorders. A 35-year-old male admitted for the evaluation of renal dysfunction and recurrent bone fractures was diagnosed as having Klinefelter's syndrome by endocrinological examinations and sex chromosome analysis. He has suffered from diabetes mellitus for more than ten years. The serum FSH and LH levels were high together with low free testosterone and estradiol levels. There was a discrepancy between basal serum GH and somatomedin-C levels. On admission, thyroid function revealed thyrotoxicosis with low radioactive iodine uptake and negative thyroid autoantibodies. During hospitalization, serum FT3 and FT4 levels were gradually decreased and serum TSH levels became elevated, leading to the diagnosis of subacute thyroiditis. Serum ACTH levels showed high basal levels with delayed, exaggerated responses to insulin-induced hypoglycemia. Rapid ACTH test (1-24ACTH 0.25 mg) showed low cortisol responses and many of the adrenocortical steroids in plasma and urine were low or low normal. Furthermore, bone mineral density (BMD) by DEXA showed marked osteoporosis. Possible mechanisms underlying these varied endocrine disorders remain to be elucidated.

A rare case of idiopathic hypoparathyroidism with varied neurological manifestations

A 47-year-old man was admitted for evaluation of unsteady gait, postural instability, and dysarthria. On admission, neurological examinations revealed cerebellar ataxia, extrapyramidal signs including parkinsonism and positive Trousseau's sign. Laboratory findings revealed severe hypocalcemia and hyperphosphatemia, and serum intact parathyroid hormone was not detectable. Brain computed tomography revealed severe calcification of basal ganglia and dentate nuclei. He was diagnosed as idiopathic hypoparathyroidism; treatment with 1 alpha (OH) vitamin D3 brought marked improvement of neurological manifestations. We report a rare case of idiopathic hypoparathyroidism presenting with extrapyramidal and cerebellar dysfunction with a review of literature.

A new family of Boucher-Neuhäuser syndrome: coexistence of Holmes type cerebellar atrophy, hypogonadotropic hypogonadism and retinochoroidal degeneration: case reports and review of literature

The association of familial hypogonadism with progressive cerebellar ataxia is only rarely encountered, and the exact link between the symptoms remains unknown. We report here two sisters presenting with Holmes type cerebellar ataxia, hypogonadotropic hypogonadism and retinochoroidal degeneration recently diagnosed as Boucher-Neuhäuser syndrome. There was consanguinity between the parents of the affected individuals and the condition seemed to be inherited as an autosomal recessive defect. On endocrinological examinations, in both cases, the responses of LH and FSH to LH-RH (100 micrograms) were impaired even after repetitive stimulation with LH-RH (400 micrograms, 7 days), suggesting that the hypogonadism was due to a primary pituitary disturbance. Impaired GH responses to GRF (100 micrograms) and insulin-induced hypoglycemia (0.1 U/kg) were also noted. The two sisters shared an almost identical clinical and endocrinological picture. Their karyotypes were 46, XX. They had been treated for primary and secondary amenorrhea at the age of 20 years and neurological problems had started at the age of 30 years. This unique family displays clinical evidence of a possible common mechanism responsible for a progressive hypothalamo-pituitary and cerebellar impairment of late onset.

Familial thyroxine-binding globulin deficiency associated with hyperthyroidism

A 24-year-old woman with familial thyroxine-binding globulin (TBG) deficiency associated with hyperthyroidism is reported. Thyroid-stimulating hormone (TSH)-binding inhibitor immunoglobulin (TBII) was negative, whereas thyroid-stimulating antibody (TSAb) was positive. Serum thyroxine-binding globulin (TBG) levels were extremely low, and remained low even after the normalization of thyroid function with methimazole (MMI) treatment. The serum TBG level of the mother of patient was also below the normal lower limit. Genetic analysis revealed single nucleotide deletion, common among Japanese with complete TBG deficiency (TBG-CD), from the allele-specific amplification of the TBG genes of the patient.

Boucher-Neuhauser syndrome associated with hypocalciuric hypercalcemia

A 52-year-old woman was diagnosed as having cerebellar ataxia, hypogonadotropic hypogonadism and retinochoroidal degeneration, the so-called, "Boucher-Neuhauser" syndrome proposed by Limber et al (Am J Med Genet 33:409, 1989). In addition, laboratory findings showed the elevation of serum calcium (Ca) levels, low urinary Ca excretion, and exaggerated reabsorption of filtrated Ca (FECa:0.14%), suggesting complication of hypocalciuric hypercalcemia. This is a very rare case of Boucher-Neuhauser syndrome associated with hypocalciuric hypercalcemia.

Diffusion and metabolism of prednisolone farnesylate in viable skin of the hairless mouse

The diffusion and metabolism of prednisolone 21-farnesylate were investigated in viable skin of the hairless mouse in vitro. The prodrug ester was extensively metabolized in viable skin, while it was stable in the donor and receptor solutions. The rate of appearance of the prodrug and its metabolite prednisolone was markedly influenced by the direction of the skin placed between the in vitro diffusion half-cells. The rate of bioconversion of the prodrug was determined as a function of the distance from the surface of the skin. The prodrug was increasingly metabolized with the distance from the surface of the skin, indicating that the responsible enzymes are enriched in the lower layers of the viable skin. A model with linearly increasing enzyme activity in the viable skin accounts for the in vitro profiles of the diffusion/metabolism of the prodrug in the viable skin of hairless mouse.