Comparison of the depth profiles of water and water-binding substances in the stratum corneum determined in vivo by Raman spectroscopy between the cheek and volar forearm skin: effects of age, seasonal changes and artificial forced hydration

BACKGROUND

Dermatologists and cosmetic scientists are becoming increasingly interested in stratum corneum (SC) hydration because the SC plays an important role in keeping the skin surface soft and smooth. However, conventional in vivo noninvasive methods do not provide direct information about the depth profiles of water content or SC components that hold water.

OBJECTIVES

To study the depth profiles of water and SC components in vivo by Raman spectroscopy, and to analyse the changes due to age, anatomical location, season and water application.

METHODS

In vivo Raman spectra of the skin of the cheek and the volar forearm were obtained from 50 healthy Japanese volunteers of different ages (age range 22-76 years) with a confocal Raman spectrometer. The depth-dependent profiles of water and of SC water-binding components were calculated from the respective Raman spectra.

RESULTS

The depth profile of the SC water content was observed in a pattern ranging from around 30% (water/wet tissue) at the outermost layer of the SC to about 70% at the deeper living layer. Although the water content at a depth of 10-30 microm in the forearm skin tended to be lower in older subjects than in younger subjects, no such difference was found in the much thinner SC of the cheek. Moreover, there was no seasonal difference in depth profile of water content from the mid part of the SC to an 80-microm depth from the skin surface both in the cheek and in the forearm. The water content of all the evaluated SC components showed a gradual decrease from the surface to deeper portions. The mean amounts of lactate in the forearm skin and cholesterol in the cheek skin were significantly higher in younger subjects than in older subjects. In contrast, the levels of free amino acids and trans-urocanic acid were higher in the forearm skin of older subjects than in younger subjects. The relative amounts of urea and lactate were the highest in summer, when that of trans-urocanic acid was the lowest. Prolonged water application on the forearm skin even for 90 min resulted in a remarkable increase in water content throughout the SC, even reaching the granular layer, which was only gradually released from the upper part of the SC after discontinuation of the hydration procedure.

CONCLUSIONS

Our present findings suggest that changes in the concentration depth profiles of water, free amino acids and lipids in the skin depend on age, anatomical site and season. These findings indicate the important roles played by various water-holding substances in the SC in the regulation of SC water content.

A new method for detecting the abomasal position and characteristics of movement at the onset of the left displacement of the abomasum in cows

A new method has been developed by us to observe the movements of the abomasum by using a magnet and digital magnetometer. Four cows with left displacement of the abomasum underwent conventional correction by rolling without tacking. A doughnut-type magnet was sutured to the pyloric region in a routine operation. The same was done in three control cows. The position of the pyloric region was observed with a digital magnetometer from outside the cow's body. The magnets in the pyloric region of the control cows were located at the right side of the abdominal cavity at 10-30 cm anterior to the udder base, and moved slightly in various directions within the span of a day. On the other hand, the magnets in the pyloric region of cows with abomasal displacement moved widely in the abdominal cavity from the normal right side to the abnormal left front side. A large movement of the magnet from the normal right side to the abnormal left side of the abdominal cavity was observed within 12 h of the onset of abomasal displacement.

New regulatory mechanisms for human extravillous trophoblast invasion

Human extravillous trophoblasts (EVT) invade maternal deciduas and reconstructed maternal spiral arteries during early placentation. However, the precise regulatory mechanisms to induce EVT invasion toward arteries and/or to protect EVT from further invasion have not been well understood. Recently, it was found that EVT that had already ceased their invasion, specifically expressed cluster of differentiation (CD9) and dipeptidyl peptidase IV (DPPIV) on their cell surface. In addition, EVT migrating to maternal spiral arteries expressed CC chemokine receptor type-1 (CCR-1), which is a chemokine receptor for regulated on activation normal T cell expressed and secreted (RANTES) and so on. CD9 is associated with integrin molecules on the cell surface and is considered to modulate integrin function. In contrast, DPPIV is a cell surface peptidase that can metabolize RANTES at extracellular sites before its accessing to the chemokine receptors. In vitro functional assay showed that CD9, DPPIV and RANTES are involved in the regulation for EVT invasion. From these findings, it can be proposed that CD9 and DPPIV, including chemokines, are new regulatory factors for human extravillous trophoblasts. (Reprod Med Biol 2005; 4: 189-195).

Laminin and fibronectin concentrations of the follicular fluid correlate with granulosa cell luteinization and oocyte quality

Background and Aims:  Progesterone production of human cultured luteinizing granulosa cells was reported to be modified by extracellular matrix, suggesting that extracellular matrix regulates luteinization of granulosa cells after ovulation. In the present study, the relationship among laminin, fibronectin, progesterone and estradiol in follicular fluid along with oocyte quality was analyzed to estimate the physiological role of extracellular matrix in follicular luteinization and oocyte quality during ovulation. Methods and Results:  Follicular fluid was collected at oocyte pick-up from the patients undergoing in vitro fertilization treatment and intracytoplasmic sperm injection. The concentrations of laminin, fibronectin, progesterone and estradiol in the follicular fluid were measured by enzyme immunoassay and radioimmunoassay. The morphology of oocytes were also assessed during the procedure of intracytoplasmic sperm injection and was classified into normal and abnormal groups. The fibronectin concentration was higher in the normal ooplasm group than in the abnormal group, but it did not correlate with estradiol or progesterone concentration. However, laminin concentration significantly correlated with that of progesterone, but not with cytoplasm morphology of oocytes. There was no difference in estradiol or progesterone concentration between the normal and abnormal groups. Conclusion:  These findings suggest that extracellular matrix plays some roles in regulating human granulosa cell luteinization and oocyte quality during ovulation. (Reprod Med Biol 2004; 3: 43-49).

Ephrin B1 is expressed on human luteinizing granulosa cells in corpora lutea of the early luteal phase: the possible involvement of the B class Eph-ephrin system during corpus luteum formation

Ephrins and their Eph receptors are both membrane-bound proteins that function in various cell-cell recognition processes, such as morphogenesis and angiogenesis. In this study we examined the expression of B class ephrins-Ephs in the human ovary during corpus luteum formation, a process of tissue remodeling accompanied by angiogenesis. RT-PCR analysis detected mRNAs for Eph B1, B2, and B4 and ephrin B1 and B2, but not Eph B3 and B6 or ephrin B3, in human corpora lutea of the early luteal phase. By immunohistochemistry, ephrin B1 was moderately expressed on theca interna cells, but was expressed at a low level on granulosa cells in the preovulatory follicles. After ovulation, a rapid increase in ephrin B1 expression was observed on luteinizing granulosa cells, whereas its expression on luteinizing theca interna cells decreased. The mRNA expression of ephrin B1 in luteinizing granulosa cells was confirmed by Northern blotting. Flow cytometry showed that ephrin B1 was expressed on the surface of isolated luteinizing granulosa cells. Moreover, these cells had the ability to bind to recombinant Eph B2-Fc fusion protein. These findings suggest that ephrin B1-expressing granulosa cells can directly interact with Eph-bearing cells during corpus luteum formation in vivo, suggesting that Eph-ephrin system is involved in this process.

The effect of acupuncture on the coronary arteries as evaluated by coronary angiography: a preliminary report

The Neiguan acupuncture point (EH-6) of the heart meridian is often used for circulatory disorders. To clarify this effect, we measured coronary diameters in patients with angina pectoris following acupuncture stimulation using cardioangiography. Two kinds of acupuncture stimulation, the leaving needle (LN) and the sparrow pecking method (SPM), were employed for this study. No significant differences were found between LN and SPM. Concerning the pattern of coronary reaction, coronary constriction following acupuncture showed a relationship to patients with vasospastic angina. Coronary dilation following acupuncture showed a relationship to patients with Syndrome X. The mean dilatation with acupuncture was 68.8% of that caused by isosorbide dinitrate. These findings may help to clarify the mechanism of acupuncture treatment.

Human endometrial epithelial cells express ephrin A1: possible interaction between human blastocysts and endometrium via Eph-ephrin system

Eph receptor tyrosine kinases and their cell membrane-bound ligands, ephrins, are well known to function in cell-to-cell interaction and to play an important role in cell migration and adhesion during embryonic development in mammals. To investigate the involvement of the Eph-ephrin system in human embryo implantation, the expression of Eph receptors and ephrins was examined in human blastocysts and the endometrium. Immunohistochemical examination showed that ephrin A1 was expressed on human endometrial luminal and glandular epithelial cells in both the proliferative (cycle d 8-13; n = 8) and secretory (cycle d 18-24; n = 7) phases. RT-PCR analysis of isolated endometrial epithelial cells and stromal cells showed that ephrin A1 mRNA was predominantly expressed in endometrial epithelial cells. Northern blot analysis also confirmed the expression of ephrin A1 mRNA in the endometrium. In addition, nested RT-PCR analysis revealed the mRNA expression of Eph A1, one of the representative receptors for ephrin A1, in human blastocysts obtained from patients undergoing in vitro fertilization treatment. These findings indicate a possible interaction between human blastocysts and endometrial epithelial cells via the Eph-ephrin system. Because intracytoplasmic signals are induced by Eph receptors after ephrin stimulation, this system may be involved in the activation process of the human embryo during the implantation period.

Antitumor effect of reduction of 150-kDa oxygen-regulated protein expression in human prostate cancer cells

Heat shock proteins (HSPs)/stress proteins are molecular chaperones that are induced by various environmental and physiological stimuli. Evidence of the relations between the expression of HSPs and the regulation of cell growth or transformation has accumulated. The 150-kDa oxygen-regulated protein (ORP150), a new member of HSP family, functions as a molecular chaperone in the endoplasmic reticulum. We have examined whether transduced antisense ORP150 cDNA reduces tumorigenicity and angiogenicity. Relations between these stress proteins and cancer and possibilities for anticancer gene therapy are described.

[Prospects for molecular research in urological oncology: bladder cancer]

This report consists of a description of our research findings relating to the mechanism of cancer metastasis and target molecules for early diagnosis or cancer therapy. First, we investigated the significance of metastasis-related genes expressed to various extents in three human bladder cancer cell lines using two in vivo models. The relationship between the gene expression pattern and the behavior of cancer cells implicated a loss of E-cadherin expression as a critical factor in facilitating the progression of bladder cancer. Second, we examined the expression of human telomerase reverse transcriptase (hTERT) mRNA in voided urine samples in patients with bladder cancer. Reverse transcription-polymerase chain reaction (RT-PCR) analysis showed a higher positive rate as compared with cytological examination, suggesting that the expression of hTERT in urine samples may be a useful diagnostic marker for bladder cancer. Finally, we searched for a molecule to which antisense can be applied as a treatment modality. The 150 kDa oxygen regulated protein (ORP 150), a kind of heat shock proteins, functions as a molecular chaperone in the endoplasmic reticulum. We demonstrated that the adenoviral-mediated antisense ORP150 cDNA transfer resulted in the suppression of vascular endothelial growth factor (VEGF) expression and tumor growth in vivo. In addition, the significant correlation between ORP150 and matrix metalloproteinase 2 (MMP-2) expression was observed in bladder cancer, suggesting that ORP150 functions as a molecular chaperon to MMP-2 secretion for tumor invasion. Anti-sense ORP150 may therefore have a potentially stronger antitumor effect because of its multitargeting capability as a molecular chaperone.

Expression and adhesive ability of gicerin, a cell adhesion molecule, in the pock lesions of chorioallantoic membranes infected with an avian poxvirus

The expression and adhesive activities of gicerin, a cell adhesion protein, in the pock lesions on chicken chorioallantoic membranes (CAM) infected with an avian poxvirus were studied. In normal CAMs, gicerin was found on the flattened epithelial cells, and neurite outgrowth factor (NOF) was in the basement membrane. However, in the pock lesions on infected CAMs, gicerin was overexpressed on the cell membranes of hyperplastic epithelial cells forming thick epithelial layers. Neurite outgrowth factor was also found mainly in the basement membrane, but occasionally showed aberrant expression among hyperplastic cells. In vitro analyses, using the dissociated cells from pock lesions, demonstrated that an anti-gicerin polyclonal antibody inhibit cell aggregation activity and cell adhesion to NOF. These results suggest that gicerin might promote the cell-cell and cell-extracellular matrix protein bindings of the hyperplastic epithelial cells by its homophilic and heterophilic adhesive activities, and contribute to pock formation on the infected CAMs.

A conditional replication-competent adenoviral vector, Ad-OC-E1a, to cotarget prostate cancer and bone stroma in an experimental model of androgen-independent prostate cancer bone metastasis

Prostate cancer has a high propensity to metastasize to bone, which often resists hormone, radiation, and chemotherapies. Because of the reciprocal nature of the prostate cancer and bone stroma interaction, we designed a cotargeting strategy using a conditional replication-competent adenovirus to target the growth of tumor cells and their associated osteoblasts. The recombinant Ad-OC-E1a was constructed using a noncollagenous bone matrix protein osteocalcin (OC) promoter to drive the viral early E1a gene with restricted replication in cells that express OC transcriptional activity. Unlike Ad-PSE-E1a, Ad-OC-E1a was highly efficient in inhibiting the growth of PSA-producing (LNCaP, C4-2, and ARCaP) and nonproducing (PC-3 and DU145) human prostate cancer cell lines. This virus was also found to effectively inhibit the growth of human osteoblasts and human prostate stromal cells in vitro. Athymic mice bearing s.c. androgen receptor-negative and PSA-negative PC-3 xenografts responded to a single intratumoral administration of 2 x 10(9) plaque-forming unit(s) of Ad-OC-E1a. In SCID/bg mice, intraosseous growth of androgen receptor-positive and PSA-producing C4-2 xenografts responded markedly to i.v. administrations of a single dose of Ad-OC-E1a. One hundred percent of the treated mice responded to this systemic Ad-OC-E1a therapy with a decline of serum PSA to an undetectable level, and 80% of the mice with PSA rebound responded to the second dose of systemic Ad-OC-E1a. Forty percent of the mice were found to be cured by systemic Ad-OC-E1a without subsequent PSA rebound or tumor cells found in the skeleton. This cotargeting strategy shows a broader spectrum and appears to be more effective than systemic Ad-PSE-E1a in preclinical models of human prostate cancer skeletal metastasis.

Intermetatarsophalangeal bursitis induced by a plantar epidermal cyst

A 44-year-old woman was admitted to the authors' institution for evaluation of two masses in the right forefoot. Standard radiographs showed foci of calcification within the mass. Magnetic resonance imaging and macroscopic findings during surgery revealed the lesion was composed mainly of two different portions: dorsal cystic masses and a solid mass in the plantar side of the fifth metatarsal head. Histologic and immunohistochemical examinations showed that the former was an intermetatarsophalangeal bursitis induced by keratinous material, whereas the latter was a ruptured epidermal cyst. To the best of the authors' knowledge, the current case is the first report of intermetatarsophalangeal bursitis caused by an untreated epidermal cyst.

[Correlation between expression of metastasis-related genes and lymph node metastasis in testicular cancer]

To investigate the factors related to lymph node metastasis of testicular germ cell tumors, we first established a seminoma orthotopic model with lymph node metastasis in SCID mice by inoculating small fragments from subcutaneous xenografts. Second, we compared the expression patterns of metastasis-related genes of the seminoma xenografts and of the TCam-2 cells which were established as a seminoma cell line from a primary testicular seminoma. Third, we immunohistochemically analyzed human germ cell tumors (25 seminomas, 17 nonseminomas) using monoclonal antibodies to CD34, VEGF, VEGF-C, Flt-4, MMP-2 and E-cadherin. Testicular seminoma xenografts grew in 32/32 (100%) of the inoculated mice, of which 15 (47%) developed macroscopic metastasis to the renal hilar lymph node. Circulating tumor cells were detectable by using a PCR assay for the human beta-globin gene in 25/32 (78%) mice, although metastatic foci were not histologically evident in the visceral organs, including lungs, liver, kidneys and spleen. This may reflect the lymphophilic characteristics of the seminoma cells used. Regarding mRNA expression of metastasis-related genes, an increased expression of MMP-2 and VEGF compared with that in the s.c. xenografts was demonstrated by RT-PCR assay in the testicular seminoma xenografts. In addition, uPAR, MMP-1, MMP-2, MT1-MMP and MT3-MMP showed a a stronger expression and PAI-2 a weaker expression in the seminoma xenografts than did TCam-2 cells. These results suggest a higher metastatic potential of the seminoma xenografts, especially testicular xenografts, as compared with TCam-2 cells. In the immunohistochemical study, a significant correlation was found between MMP-2 expression and lymph node metastasis, which is compatible with the results for the metastasis-related gene expression from the seminoma xenografts.

Intrarenal varix mimicking a cystic renal tumor

BACKGROUND

A case of intrarenal varix in a 60-year-old woman is reported.

METHODS/RESULTS

The preoperative diagnosis was cystic tumor in the central part of the left kidney. Retrospectively, gadolinium-enhanced magnetic resonance (MR) imaging demonstrated a layered gadolinium sign, indicating the vascular nature of the mass.

CONCLUSIONS

Our experience shows that urologists should be aware of the possible presence of a renal cystic mass of vascular origin and of the usefulness of gadolinium-enhanced MR examination for making an identification.

Anti-obesity effects of lipase inhibitor CT-II, an extract from edible herbs, Nomame Herba, on rats fed a high-fat diet

OBJECTIVE

To investigate the inhibitory effects of CT-II, extract of Nomame Herba, on lipase activity in vitro and on obesity in rats fed a high-fat diet in vivo.

DESIGN

The assay for the inhibitory effect of CT-II on lipase activity was performed by measuring released free fatty acids after the incubation of the medium with CT-II, porcine pancreatic lipase and triolein (experiment 1). In vivo experiments, lean rats or obese rats (570-718 g) were fed a high-fat diet containing 60% fat with or without CT-II for 8 weeks (experiment 2), for 14 days (experiment 3) or for 12 weeks (experiment 4), respectively.

MEASUREMENT

The time course of body weight, food intake, organ weight (parametrial fat, liver, heart and kidney) and plasma parameters (triglyceride, total cholesterol, glucose, AST, ALT and insulin), fecal output of total fat and total cholesterol were measured. Hepatic histological examinations were also performed.

RESULTS

CT-II inhibited the porcine lipase activity dose-dependently in vitro (experiment 1). Body and liver weight were reduced and hepatic histological examination showed an amelioration of fatty liver in CT II treated animals (experiment 2). CT-II significantly inhibited body weight gain and plasma triglyceride elevation in a dose-dependent manner, without affecting food intake in lean rats fed the high-fat diet. Elevated plasma AST and ALT were also decreased (experiment 3). When obese rats fed the high-fat diet were treated with CT-II for up to 6 months, body weight was initially reduced and thereafter weight gain was significantly suppressed. Total body fat was also significantly reduced and significant reduction of plasma AST and ALT was observed (experiment 4).

CONCLUSIONS

These results demonstrated that the lipase inhibitor CT-II is effective in preventing and ameliorating obesity, fatty liver and hypertriglyceridemia in rats fed a high-fat diet.

Uptake of BrdU in olfactory and respiratory epithelium of rabbits with experimental sinusitis

Sinusitis was induced in six rabbits in order to evaluate its influence on the proliferation of cells in the olfactory epithelium compared with the respiratory epithelium during conservative antibiotic therapy. Then 1% ofloxacin was injected into the paranasal sinuses. Three normal rabbits were not administered any treatment and served as controls. The rabbits were sacrificed under intravenous anesthesia and the olfactory and respiratory mucosa was excised 24 hours after intravenous administration with the labeling reagent 5-bromo-2'-deoxyuridine (BrdU). The extent of cell proliferation in these tissues was estimated by immunohistochemical staining with BrdU-specific antibody. The uptake of BrdU was significantly increased (p = 0.0099) in the respiratory mucosa, but not in the olfactory mucosa. Furthermore, in olfactory epithelium, 79.2% and 16.7% of all BrdU-positive cells were olfactory and basal, respectively. Thus, turnover of epithelial cells due to sinusitis was not as accelerated in the olfactory mucosa as in the respiratory mucosa during antibiotic treatment.

Liposarcoma associated with multiple intramuscular lipomas. A case report

A 71-year-old slender, previously healthy man was admitted to the authors' institution because of a huge painless mass in his left scapular area. Physical examination revealed a second soft tissue mass in his right scapular region and a third soft tissue mass in the anterior side of his right shoulder. Surgical treatment including marginal resection of the second and third small masses followed by wide local resection of the huge tumor was performed. Histologic examination showed that the first mass was a well differentiated lipomalike liposarcoma, whereas the second and third lesions were identified as intramuscular lipomas. A review of the literature showed two cases of retroperitoneal liposarcoma associated with multiple subcutaneous lipomas and two cases of liposarcoma involving an extremity associated with multiple subcutaneous lipomas. There is no previous report in which intramuscular liposarcoma was associated with multiple intramuscular lipomas.

[Clinical efficacy and reduction effect on prostatic volume of chlormadinone acetate combined with tamsulosin hydrochloride in benign prostatic hyperplasia patients insufficiently treated with tamsulosin hydrochloride only]

Alpha adrenergic blocker has become the first choice in the medical treatment of benign prostatic hyperplasia (BPH). The efficacy of alpha adrenergic blocker has been suggested to be related to the prostatic tissue components, and to be ineffective in treating the clinical symptoms caused by BPH in some cases. The efficacy and prostate reduction of an anti-androgenic agent, chlormadinone acetate, combined with alpha adrenergic blocker, tamsulosin hydrochloride, were evaluated using 40-BPH patients insufficiently treated with tamsulosin hydrochloride alone. Fifty mg of chlormadinone acetate and 0.2 mg of tamsulosin hydrochloride were administered orally once a day for 16 weeks to patients with a prostate subjective symptoms score, I-PSS, of greater than 13 or a peak flow rate of less than 12 ml/s, even after the treatment with 0.2 mg of tamsulosin hydrochloride alone for more than four weeks. Total I-PSS decreased significantly after four weeks. The total irritative symptom score did not change for 16 weeks, but the total obstructive symptom score decreased significantly, as did the total I-PSS. In objective data, the estimated volume of both total prostate and the transition zone on transrectal ultrasonogram decreased significantly at the end of the treatment, and the peak flow rate decreased significantly after 12 weeks. These findings suggest that the addition of chlormadinone acetate may be a reasonable alternative in the treatment of BPH patients responding insufficiently to tamsulosin hydrochloride alone, and that combination therapy using chlormadinone acetate and tamsulosin hydrochloride may be useful for BPH patients with serious obstructive symptoms.

Enhancing effect of 2-O-alpha-D-glucopyranosyl-L-ascorbic acid, a stable ascorbic acid derivative, on collagen synthesis

The objective of the present study was to compare 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G) with ascorbic acid (AA) and ascorbic acid 2-phosphate (AA-2P) concerning the promotion of collagen production in human skin fibroblasts. Though AA-2G was still observed to be promoting collagen synthesis at the same level on the 8th day of the culture, collagen synthesis was seen to decrease on the fifth day of culturing with AA and AA-2P. This sustained collagen synthesis-promoting action is considered to be a major feature of the novel vitamin C derivative, AA-2G by conducting an experiment in which an alpha-glucosidase inhibitor was present, it was shown that AA-2G exerts its collagen synthesis-promoting action after being decomposed to AA by alpha-glucosidase. Further, we observed that for AA-2G, even on the 8th day of the culture, the amount of AA in the fibroblasts was virtually unchanged from the beginning of the experiment, whereas, in the case of adding AA and AA-2P, virtually no AA was detectable in the culture medium on the fifth day. These findings suggests that AA-2G is decomposed to AA by alpha-glucosidase in the cells. This AA promotes collagen synthesis, which is prolonged through AA-2G's sustained decomposition.

In vitro and in vivo prolonged biological activities of novel vitamin C derivative, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), in cosmetic fields

The biological activity of the novel vitamin C derivative, 2-O-alpha-D-glucopyranosyl-L-ascorbic acid (AA-2G), was evaluated in vitro and in vivo. The percutaneous absorption of AA-2G was determined in five Japanese males. The excretion of ascorbic acid (AA) in the subjects administered AA-2G was sustained for a longer period than in the subjects administered ascorbic acid 2-phosphate (AA-2P), which is a conventional vitamin C derivative. An analysis of the distribution of AA in the skin showed that small black specks assumed to be AA were observed in the epidermis even 3 d after applying AA-2G. The melanin synthesis in B16 melanoma cells was inhibited more by AA-2G than by AA-2P, and AA-2G also prevented more UV-induced damage of human skin keratinocytes and fibroblasts than AA-2P did. From these in vivo and in vitro results, it is supposed that the conversion of AA-2G to AA is sustained for a long time compared with that of AA-2P, and that AA-2G is an effective and available compound having vitamin C activity in human subjects.

Effects of a 7-day infusion of glucose on insulin secretion in vivo and in vitro in ventromedial hypothalamic-lesioned obese rats

Excessive stimulation of insulin secretion may be one cause of the beta-cell dysfunction induced by hyperglycemia. We investigated a possible link between the prior endogenous hypersecretion of insulin and this dysfunction by performing a 7-day glucose infusion (50% wt/vol, 1.2 ml/h) on ventromedial hypothalamic VMH-lesioned hyperinsulinemic rats. Intravenous glucose tolerance tests (i.v.GTT 1.0 g/kg) revealed that a 3-day glucose infusion enhanced the insulin responses in both the sham- and VMH-lesioned rats compared with saline infusions. A similar 7-day glucose infusion enhanced the insulin response to glucose in sham-lesioned rats but not in VMH-lesioned rats. Batch-incubation of islets isolated from sham-lesioned rats showed an enhanced insulin response to glucose after 7 days of glucose treatment compared with the saline infusions. Conversely, the glucose infusion in VMH-lesioned rats markedly suppressed the in vitro insulin response. In sham- and VMH-lesioned rats, similar islet insulin contents were produced by saline and glucose treatments. Electron microscopy revealed that glucose infusions impaired the granule-releasing function of the beta-cells in VMH-lesioned rats, while insulin synthesis was accelerated in either group. These findings support the notion that excessive secretion is partly responsible for the beta-cell dysfunction induced by hyperglycemia without signs of exhaustion.

Effect of 5-[3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-benzodioxole HCl (MKC-242), a novel 5-HT1A-receptor agonist, on aggressive behavior and marble burying behavior in mice

Behavioral effects of 5-[3-[((2S)-1,4-benzodioxan-2-ylmethyl)amino]propoxy]-1,3-be nzodioxole HCl (MKC-242), a novel 5-HT1A-receptor agonist, were evaluated using animal models of anxiety and obsessive compulsive disorder and compared against reference compounds. MKC-242 suppressed foot shock-induced fighting behavior without loss of motor coordination in mice as the reference compounds did. The ED50 values of MKC-242, buspirone, tandospirone and diazepam were 1.7, 42, 80 and 2.0 mg/kg, p.o., respectively. The duration of the suppression of fighting by MKC-242 was longer than those of buspirone and tandospirone and comparable to that of diazepam. Similar results were also obtained with the water-lick conflict test in rats. The plasma concentration of MKC-242 in rats was much higher than the reported value of buspirone during 0.25-6 hr after oral administration. In addition, MKC-242 reduced marble burying behavior without reduction of motor activity. Fluoxetine, tandospirone and diazepam also reduced the behavior at non-sedative doses. These findings indicate that MKC-242 possesses a longer-lasting anxiolytic effect than azapirones. This might be due to the high concentration of the compound in plasma. In addition, it is also suggested that MKC-242 possesses an antiobsessional effect.