Highly enhanced permeability of blood-brain barrier induced by repeated administration of endothelin-1 in dogs and rats

The effects of intracisternal administration of endothelin-1 on blood-brain barrier permeability were examined in dogs and rats. Single doses of endothelin-1 elevated blood-brain barrier permeability about two times compared with control groups in both species. However, repeated dosing with endothelin-1 at a 24 hr intervals caused a highly enhanced disruption of blood-brain barrier permeability in dogs, but not in rats, whereas the repeated administration with a 48 hr interval markedly increased the blood-brain barrier permeability in both species of animals (dogs: 923%, rats: more than 661%). Moreover, this abnormally enhanced permeability of blood-brain barrier in dogs was completely blocked by pretreatment with the endothelin ET-A receptor selective antagonist, S-0139, administered prior to either the first or second dosing with endothelin-1. From these results, we conclude that a repeated attack of endothelin-1 from the adventitial site of brain blood vessels produces a severe disruption of blood-brain barrier permeability through an endothelin ET-A receptor-mediated process.     

Nicotine-induced inflammatory decreasing effect on passive skin arthus reaction in paraventricular nucleus-lesioned wistar rats

To evaluate the relationship between nicotine and immunological inflammation, we investigated the effects of nicotine on plasma extravasation of the passive skin Arthus reaction, elicited 4 hr after sensitizing skin with antiserum, and serum corticosterone levels in rats. Pretreatment with a single subcutaneous injection of nicotine (0.4 or 0.8 mg/kg) 30 or 60 min. before antigen challenge attenuated the passive skin Arthus reaction immunological inflammation. Serum corticosterone levels were dose-dependently increased 30 and 60 min. after nicotine administration. Both markers co-varied with a similar dose-response and time course after the nicotine-treatment. In addition, we also examined these nicotine-induced responses after bilateral lesions of the hypothalamic paraventricular nucleus; both the nicotine-induced suppression of immunological inflammation and the increased serum corticosterone levels were attenuated in bilateral paraventricular nucleus-lesioned animals. Moreover, the immunological inflammatory decreasing effects of a single subcutaneous injection of nicotine (0.4 mg/kg) were antagonized by intraperitoneal preinjection with mecamylamine (1.0 mg/kg; blocking the brain nicotinic acetylcholine receptors) as well as by subcutaneous preinjection with mifepristone (30 mg/kg; a glucocorticoid receptor antagonist) but not by intraperitoneal preinjection with hexamethonium (2.0 mg/kg; a peripheral nicotinic acetylcholine receptors antagonist). Finally, intraperitoneal preinjection with cycloheximide (2 mg/kg), a protein synthesis inhibitor, abolished both the inhibitory effect of nicotine (0.4 mg/kg) on the dye leakage and the elevation of blood corticosterone levels. These findings indicate that the nicotine-induced decreasing effect on immunological inflammatory response may be related to serum corticosterone levels elevated by an activation of the paraventricular nucleus through the brain nicotinic acetylcholine receptors.     

Possible benefits of triamcinolone-assisted pars plana vitrectomy for retinal diseases

PURPOSE: To study the advantages and complications of triamcinolone acetonide (TA)-assisted pars plana vitrectomy (PPV) for various retinal diseases. METHODS: This report is an interventional case series and nonrandomized study. One hundred seventy-seven eyes from 158 patients underwent PPV with or without TA. Group TA(+) consisted of 94 eyes and group TA(-) consisted of 83 eyes. The improvement in vision and postoperative complications were prospectively studied. RESULTS: Sixty-two percent of the eyes in group TA(+) and 49% of the eyes in group TA(-) had improved vision after surgery (P = 0.34). Twelve eyes in group TA(+) and 12 eyes in group TA(-) had an intraocular pressure higher than 21 mmHg after the operation, with no statistically significant difference (P = 0.63). Four eyes with proliferative diabetic retinopathy in group TA(+) and five eyes with proliferative diabetic retinopathy in group TA(-) needed an additional filtering surgery. Group TA(+) (five eyes) had a lower incidence (P = 0.041) of reoperation caused by preretinal fibrous membrane formation than group TA(-) (13 eyes). No apparent corneal disorder or infectious signs were found in any eyes. CONCLUSIONS: Triamcinolone acetonide-assisted PPV appears to be potentially useful to reduce the incidence of reoperation owing to preretinal fibrosis with no serious complications.     

A novel therapeutic strategy against vascular disorders with chymase inhibitor

In vascular tissues, angiotensin II is potentially cleaved from angiotensin I by chymase and angiotensin converting enzyme (ACE). In the normal state, ACE regulates angiotensin II formation and plays a crucial role in the regulation of blood pressure, whereas chymase is stored in mast cells and has no angiotensin II-forming activity. Chymase is activated immediately upon its release into the extracellular matrix in vascular tissues after mast cells have been activated by local stimuli such as vessel injury by grafting or a balloon catheter. In dog grafted veins, vascular proliferation, chymase activity, angiotensin II concentration and mRNA levels of fibronectin, collagen I and collagen III were significantly increased after the operation, while they were significantly suppressed by a chymase inhibitor. A clinical trial of an angiotensin II receptor blocker (ARB) for preventing restenosis after percutaneous transluminal coronary angioplasty was successful, but that of an ACE inhibitor was not. After balloon injury in dog vessels, chymase activity was signifcantly increased in the injured artery, and a chymase inhibitor and an ARB were effective in preventing the vascular proliferation, but an ACE inhibitor was ineffective. On the other hand, a chymase inhibitor, unlike an ACE inhibitor and an ARB, did not affect blood pressure. These reports indicate that local angiotensin II production by chymase is involved only in the intimal hyperplasia seen in the injured vessels. Therefore, chymase inhibitors may be useful for preventing vascular disoders without affecting blood pressure.     

Inhibitory effects of hyssop (Hyssopus officinalis) extracts on intestinal alpha-glucosidase activity and postprandial hyperglycemia

It has been known that Hyssopus officinalis (hyssop) is a herb that grows in the wild and is a source of natural antioxidants. We previously reported that a-glucosidase inhibitors, (2S, 3S)1-O-beta-D-6'-O-cinnamoylglucopyranosyl-3-(3", 5"-dimethoxy-4"-hydroxyphenyl)-1,2,3-propanetriol and (2S, 3S)1-O-beta-D-glucopranosyl-3-(3", 5"-dimethoxy-4"-hydroxyphenyl)-1,2,3-propanetriol, from the dry leaves of hyssop, were isolated. This study examined the alpha-glucosidase inhibitory effects of hyssop extracts on intestinal carbohydrate absorption in rat everted gut sac and carbohydrate-loaded hyperglycemia in mice. In the everted gut sac experiment, 10 mM sucrose- and 5 mM maltose-treated increases in glucose concentration in the serosal compartment were inhibited in the presence of 0.5 and 1.0 mg/ mL hyssop extracts, although a 10 mM glucose-induced increase in serosal glucose was not inhibited by the extracts. Additionally, hyperglycemia in sucrose- and maltose-loaded mice was significantly suppressed at an early stage, within 30 to 60 min by oral pre-administration of 300 and 100 mg/kg hyssop extracts, respectively. These findings suggest that hyssop extracts inhibited the digestion of complex carbohydrates, but not that of absorbable monosaccharide, and might be a useful supplemental food for hyperglycemia.     

Lifestyle differences between conjugal bereaved women and non-bereaved women in later life

PURPOSES: In Japan, there has been limited research regarding lifestyle of elderly bereaved. The present study was conducted to clarify lifestyle characteristics in conjugal bereaved women compared to non-bereaved women. METHODS: Subjects consisted of 872 bereaved and 643 non-bereaved elderly women aged 65 or over in T prefecture. Bereaved subjects experienced the death of a spouse in 1994 and their family structure remained unchanged after the bereavement. Non-bereaved subjects were randomly selected from community registration lists in 1995 and matched for age and area of residence. Lifestyle characteristics were obtained by home visit and interview. For the analysis, we divided the subjects into 4 groups by age and family structure. Multiple logistic regression analysis was performed to identify lifestyle characteristics of bereaved elderly women, after adjustment for physical ability and disease, as confounding factors. RESULTS: Bereaved elderly women were significantly associated with no roles at home, no hobbies, lack of contact with friends, physical inactivity, sleeplessness and irregular meal patterns compared to the non-bereaved. Analysis of the 4 groups revealed bereaved women living with family members have more unfavorable lifestyle characteristics than bereaved women living alone. Bereaved women living with family members had no roll at home and sleeplessness. CONCLUSION: Bereaved women have unfavorable lifestyle characteristics. Those living with family members had more unfavorable lifestyle than bereaved women living alone. From the preventive point of view, interventions for bereaved women are needed. This is particularly the case for bereaved women living with family members. Not only health services but also social welfare services are needed to reconstruct favorable lifestyles and maintain health and well-being.     

Lack of estrogenic or (anti-)androgenic effects of d-phenothrin in the uterotrophic and Hershberger assays

Synthetic pyrethroids are among the most common insecticides and pesticides currently in use worldwide. Recently, d-phenothrin, a synthetic pyrethroid, is suspected to have endocrine activities through the estrogen and androgen receptors. However, no study has been conducted to evaluate its potential for hormonal activity using an in vivo test specifically focused on estrogenic and androgenic activities. In this study, we evaluated the interaction of d-phenothrin (0, 100, 300 or 1000 mg/kg per day, p.o.) with estrogen- or androgen-mediated mechanisms using in vivo short-term assays. While internationally standardized protocols for the uterotrophic and Hershberger assays have not yet been fully developed, both are widely used and are being considered by the OECD as short-term screening assays for hormonal activity. The highest dose level tested for d-phenothrin was a limit dose (1000 mg/kg per day) designated in the current draft protocol by the OECD, and in fact there was no excessive systemic toxicity in both assays; slightly increased liver weight but no change of serum androgen levels in accessing anti-androgenicity. Potential estrogenic effect of d-phenothrin was evaluated by means of 3-day uterotrophic assay using immature Crj:CD(SD)IGS rats (20 days of age). No increase in uterine weight (wet or blotted) was observed following oral exposure to d-phenothrin. Reference control ethynyl estradiol (0.001 mg/kg per day) showed a significant effect in this assay protocol. A 10-day Hershberger assay using castrated peripubertal male rats measures the androgenic or anti-androgenic effects of the test chemicals on several accessory glands/tissues (the ventral prostate, dorso-lateral prostate, seminal vesicles with coagulating glands, levator ani plus bulbocavernosus muscles, glans penis and Cowper's glands). d-Phenothrin was administered by oral gavage for 10 days to castrated male Crj:CD(SD)IGS rats (7 weeks of age, rats were castrated at 6 weeks of age) with or without co-administration of 0.2 mg/kg per day testosterone propionate (subcutaneous injection on the dorsal surface). Reference controls of methyltestosterone and p,p'-DDE (100 mg/kg per day) provided significant effects in this assay protocol, whereas d-phenothrin did not show any androgenic or anti-androgenic effects. It is concluded that, based on the results of these two reliable in vivo assays, d-phenothrin exhibits no potential to cause adverse estrogenic or (anti-)androgenic effects even at dose of 1000 mg/kg per day, the limit dose designated in the current draft protocol by the OECD.     

Ionic interaction of [<Superscript>11</Superscript>C]-<Emphasis Type="Italic">N</Emphasis>, α-dimethylbenzylamine (DMBA) in rodent brain

The [S] enantiomer of [11C]-N,alpha-dimethylbenzylamine (DMBA) was synthesized by N-methylation of [S]-alpha-methylbenzylamine, and its biodistribution in mice was measured. [11C]-[S]-DMBA was rapidly distributed into the brain, heart and lungs, and considerable long-term retention in the brain was observed. The radioactive metabolites in the plasma were analyzed by liquid chromatography. Kinetic analysis using unmetabolized [11C]DMBA in the plasma as the input function was performed employing a simplified two-compartment model. The estimated distribution volumes (DV) of [11C]DMBA in the brain and heart were 6.05 and 3.95, respectively. The right striatum of the rat brain was lesioned with ibotenic acid 2 weeks before the tracer experiment. Both in vitro and in vivo autoragiographic studies were performed, and revealed significant reduction of the radioactivity levels in the lesioned striatum. On the other hand, the regional cerebral blood flow, as measured by [14C]iodoantipyrine, was not significantly altered in the lesioned striatum. These results indicate that the ionic binding component for DMBA exists mainly in neural cells rather than in glial cells. [11C]DMBA might be a useful radiotracer for detection of neural cell loss in the brain.     

Pioglitazone reduces hepatic fat content and augments splanchnic glucose uptake in patients with type 2 diabetes

The effect of pioglitazone on splanchnic glucose uptake (SGU), endogenous glucose production (EGP), and hepatic fat content was studied in 14 type 2 diabetic patients (age 50 +/- 2 years, BMI 29.4 +/- 1.1 kg/m(2), HbA(1c) 7.8 +/- 0.4%). Hepatic fat content (magnetic resonance spectroscopy) and SGU (oral glucose load- insulin clamp technique) were quantitated before and after pioglitazone (45 mg/day) therapy for 16 weeks. Subjects received a 7-h euglycemic insulin (100 mU. m(-2). min(-1)) clamp, and a 75-g oral glucose load was ingested 3 h after starting the insulin clamp. Following glucose ingestion, the steady-state glucose infusion rate during the insulin clamp was decreased appropriately to maintain euglycemia. SGU was calculated by subtracting the integrated decrease in glucose infusion rate during the 4 h after glucose ingestion from the ingested glucose load. 3-[(3)H]glucose was infused during the initial 3 h of the insulin clamp to determine rates of EGP and glucose disappearance (R(d)). Pioglitazone reduced fasting plasma glucose (10.0 +/- 0.7 to 7.5 +/- 0.6 mmol/l, P < 0.001) and HbA(1c) (7.8 +/- 0.4 to 6.7 +/- 0.3%, P < 0.001) despite increased body weight (83 +/- 3 to 86 +/- 3 kg, P < 0.001). During the 3-h insulin clamp period before glucose ingestion, pioglitazone improved R(d) (6.9 +/- 0.5 vs. 5.2 +/- 0.5 mg. kg(-1). min(- 1), P < 0.001) and insulin-mediated suppression of EGP (0.21 +/- 0.04 to 0.06 +/- 0.02 mg. kg(-1). min(-1), P < 0.01). Following pioglitazone treatment, hepatic fat content decreased from 19.6 +/- 3.6 to 10.4 +/- 2.1%, (P < 0.005), and SGU increased from 33.0 +/- 2.8 to 46.2 +/- 5.1% (P < 0.005). Pioglitazone treatment in type 2 diabetes 1) decreases hepatic fat content and improves insulin-mediated suppression of EGP and 2) augments splanchnic and peripheral tissue glucose uptake. Improved splanchnic/peripheral glucose uptake and enhanced suppression of EGP contribute to the improvement in glycemic control in patients with type 2 diabetes.     

The effects of inhaled carbon monoxide on lung injury in rats caused by lipopolysaccharide

BACKGROUND: Carbon monoxide (CO) has long been considered a toxic substance. Recent studies have revealed that CO may play an important role in intercellular signaling. We hypothesized that CO modulates the inflammatory mechanisms. METHODS: SD rats (each study group consisting of 7 animals) inhaled 250 ppm of CO one hour prior to LPS challenges. These animals were incubated for a particular period of time (four different length of time; 1, 2, 4, and 8 hours). The control group (each study group consisting of 6 animals) had been left in the room air. Both groups were instilled with LPS (1 mg) into the lungs. At the end of each period, animals were exsanguinated, broncho-alveolar lavage (BAL) and blood sampling were performed, and a part of the small intestine was harvested. PMN numbers, protein, TNF, and IL-10 concentrations in BAL fluid were measured. Plasma TNF and IL-10 were also measured. The Wet/Dry ratio of a small intestine was calculated. RESULTS: In the CO-inhalation group, the anti-inflammatory cytokine IL-10 concentration in the BAL fluid was higher at 8 hours after LPS challenge than the counterpart of room air group (37.6 +/- 11.4 pg.ml-1 vs. 92.8 +/- 31.5 pg.ml-1, P < 0.05). W/D ratio decreased (3.29 +/- 0.2 vs. 2.94 +/- 0.06, P < 0.05). CONCLUSION: These findings indicated that CO inhalation might modulate the inflammatory response to LPS. Further study is needed to prove the therapeutic role of CO inhalation without serious adverse effects.