Inhibition of compound action potentials in the frog sciatic nerve by inchinkoto, a traditional Japanese medicine used for oral mucositis

OBJECTIVE

This study aimed to determine the effects of traditional Japanese (Kampo) medicines used to treat oral mucositis on nerve conduction.

METHODS

The effects of Kampo medicines, crude drugs, and chemical compounds on compound action potentials (CAPs) were analyzed using extracellular recordings in frog sciatic nerves.

RESULTS

Among the Kampo medicines, inchinkoto demonstrated the most significant reduction in CAP amplitude, with a half-maximal inhibitory concentration (IC50) of 5.4 mg/mL. Hangeshashinto, shosaikoto, hochuekkito, and juzentaihoto also showed a significant reduction. Regarding inchinkoto, Artemisiae Capillari Spica (artemisia) was the most effective crude drug, with an IC50 of 4.2 mg/mL for CAP amplitude reduction, whereas Gardeniae Fructus (gardenia) exerted no significant effect. However, the combined use of artemisia and gardenia reduced the CAP amplitude more effectively than artemisia alone, indicating a synergistic interaction. The chemical ingredient eugenol from artemisia administered at 1 and 3 mmol/L reduced CAP amplitude, whereas other chemical ingredients administered at 0.1 and 1 mmol/L had no significant effects.

CONCLUSIONS

Inchinkoto exhibited the most effective reduction in CAP amplitude in the sciatic nerve of frogs, primarily through the action of artemisia, with potential synergistic interaction between artemisia and gardenia.

Inhibition of Retinoid X Receptor Improved the Morphology, Localization of Desmosomal Proteins, and Paracellular Permeability in Three-Dimensional Cultures of Mouse Keratinocytes

Retinoic acid (RA) plays an important role in epithelial homeostasis and influences the morphology, proliferation, differentiation and permeability of epithelial cells. Mouse keratinocytes, K38, reconstituted non-keratinized stratified epithelium in three-dimensional (3D) cultures with serum, which contains retinol (a source of RA), but the morphology was different from in vivo epithelium. The formed epithelium was thick, with loosened cell–cell contacts. Here, we investigated whether the inhibition of RA receptor (RAR)/retinoid X receptor (RXR)-mediated signaling by an RXR antagonist, HX 531, improved K38 3D cultures in terms of morphology and intercellular junctions. The epithelium formed by 0.5 μM HX531 was thin, and the intercellular space was narrowed because of the restoration of the layer-specific distribution of desmoglein (DSG)-1, DSG3 and plakoglobin (PG). Moreover, the levels of desmosomal proteins and tight junction proteins, including DSG1, DSG2, DSG3, PG, claudin (CLDN)-1 and CLDN4 increased, but the adherens junction protein, E-cadherin, did not show any change. Furthermore, CLDN1 was recruited to occludin-positive cell–cell contacts in the superficial cells and transepithelial electrical resistance was increased. Therefore, K38 3D cultures treated with 0.5 μM HX531 provides a useful in vitro model to study intercellular junctions in the non-keratinized epithelium.

Maxillofacial morphological characteristics in growing orthodontic patients with non-syndromic oligodontia

OBJECTIVE

Patients with oligodontia frequently show different types of malocclusions. However, how oligodontia affects the maxillofacial growth remains uncertain. This study aimed to investigate the maxillofacial morphological characteristics in growing patients with oligodontia.

SETTING AND SAMPLE POPULATION

The study subjects included 33 Japanese children with non-syndromic oligodontia (14 boys and 19 girls; mean age: 10.2 years) who visited the orthodontic clinic of Fukuoka Dental College Medical and Dental Hospital from 1999 to 2019.

MATERIALS AND METHODS

Cephalometric analyses were performed, and the variables measured in each subject were converted into Z scores in relation to the mean and standard deviation of the Japanese norms matched for growth stage. The one-sample t-test or Wilcoxon signed-rank test was performed to compare the mean scores in the patients with oligodontia with those of the Japanese norms.

RESULTS

Compared with the Japanese norms, patients with oligodontia showed a smaller convexity and larger A-B plane and SNB angles. The Frankfort-mandibular plane and gonial angles were smaller, whereas the height of the ramus was larger. The vertical height of the alveolar bone in the maxillary and mandibular incisors and molar areas was smaller in patients with oligodontia.

CONCLUSIONS

Patients with oligodontia showed Class III skeletal tendency with mandibular prognathism and flattened mandibular plane with a smaller gonial angle. These maxillofacial morphological features can be induced by a deficiency in the vertical growth of the alveolar bone in the maxillary and mandibular molar areas due to the lack of tooth germs.

SNAI2 is induced by transforming growth factor-β1, but is not essential for epithelial-mesenchymal transition in human keratinocyte HaCaT cells

Epithelial-mesenchymal transition (EMT) is a cellular process in which epithelial cells lose their epithelial traits and shift to the mesenchymal phenotype, and is associated with various biological events, such as embryogenesis, wound healing and cancer progression. The transcriptional program that promotes phenotype switching is dynamically controlled by transcription factors during EMT, including Snail (SNAI1), twist family bHLH transcription factor (TWIST) and zinc finger E-box binding homeobox 1 (ZEB1). The present study aimed to investigate the molecular mechanisms underlying EMT in squamous epithelial cells. Western blot analysis and immunocytochemical staining identified Slug (SNAI2) as a transcription factor that is induced during transforming growth factor (TGF)-β1-mediated EMT in the human keratinocyte cell line HaCaT. The effect of SNAI2 overexpression and knockdown on the phenotypic characteristics of HaCaT cells was evaluated. Filamentous actin staining and western blot analysis revealed that the overexpression of SNAI2 did not induce the observed EMT-related phenotypic changes. In addition, SNAI2 knockdown demonstrated almost no impact on the EMT phenotypes induced by TGF-β1. Notably, DNA microarray analysis followed by comprehensive bioinformatics analysis revealed that the differentially expressed genes upregulated by TGF-β1 were significantly enriched in cell adhesion and extracellular matrix binding, whereas the genes downregulated in response to TGF-β1 were significantly enriched in the cell cycle. No enriched gene ontology term and biological pathways were identified in the differentially expressed gene sets of SNAI2-overexpressing cells. In addition, the candidates for master transcription factors regulating the TGF-β1-induced EMT were identified using transcription factor enrichment analysis. In conclusion, the results of study demonstrated that SNAI2 does not play an essential role in the EMT of HaCaT cells and identified candidate transcription factors that may be involved in EMT-related gene expression induced by TGF-β1. These findings may enhance the understanding of molecular events in EMT and contribute to the development of a novel therapeutic approach against EMT in cancers and wound healing.

An orthodontic perspective on Larsen syndrome

Background

Larsen syndrome (LS) is a rare disorder of osteochondrodysplasia. In addition to large-joint dislocations, craniofacial anomalies are typical characteristics. In this report, we performed orthodontic analyses, including skeletal and occlusal evaluations, to examine whether the craniofacial skeletal morphology leads to the craniofacial anomalies in LS.

Case presentation

A 5 year old Japanese girl who was clinically diagnosed with LS was referred to the orthodontic clinic in the Fukuoka Dental College Medical and Dental Hospital because of a malocclusion. Clinical findings at birth were knee-joint dislocations, equinovarus foot deformities, and cleft soft palate. The patient showed craniofacial anomalies with hypertelorism, prominent forehead, depressed nasal bridge, and flattened midface. To evaluate the craniofacial skeletal morphology, cephalometric analysis was performed. In the frontal cephalometric analysis, the larger widths between bilateral points of the orbitale were related to hypertelorism. The lateral cephalometric analysis revealed the midface hypoplasia and the retrognathic mandible. These findings were responsible for the flattened appearance of the patient’s face, even if the anteroposterior position of the nasion was normal. Her forehead looked prominent in relation to the face probably because of the retrognathic maxilla and mandible. Both the study model and the frontal cephalometric analysis indicated constriction of the upper and lower dental arches. The posterior crossbite facilitated by the premature contacts had developed in association with the constriction of the upper dental arch.

Conclusions

This patient had some craniofacial anomalies with characteristic appearances in LS. It was evident that the underlying skeletal morphology led to the craniofacial dysmorphism.

Immunohistochemical study for the expression of leukocyte adhesion molecules, and FGF23 and ACE2 in P. gingivalis LPS-induced diabetic nephropathy

Objective

The present study aims to examine the expression of leukocyte adhesion molecules and renal metabolic factors in diabetic mouse kidneys with periodontal pathogen Pg-LPS-induced nephropathy.

Background

We recently reported that the glomerular endothelium expresses toll-like receptor (TLR)2 and TLR4 in diabetic environments and TLR2/4 ligand Porphyromonas (P.) gingivalis lipopolysaccharides (Pg-LPS) induce nephropathy in diabetic mice. It is thought that Pg-LPS promotes the chronic inflammation with the overexpression of leukocyte adhesion molecules and renal-specific metabolic enzymes by the recognition of Pg-LPS via TLR in the diabetic kidneys. There have been no reports of the effects of periodontopathic bacteria on the expression of leukocyte adhesion molecules and the accumulation of physiologically active substances in the kidney.

Methods

The immunohistochemical investigation was performed on diabetic mouse kidney with Pg-LPS-induced nephropathy with glomerulosclerosis in glomeruli.

Results

There were no vessels which expressed vascular cell adhesion molecule-1 (VCAM-1), E-selectin, or fibroblast growth factor (FGF) 23 in streptozotocin (STZ)-induced diabetic ICR mice (STZ-ICR), or in healthy ICR mice administered Pg-LPS (LPS-ICR). However, in diabetic ICR mouse kidneys with Pg-LPS-induced nephropathy (LPS-STZ) the expression of VCAM-1 and the accumulation of FGF23 were observed in renal tubules and glomeruli, and the expression of E-selectin was observed in renal parenchyma and glomeruli. The angiotensin-converting enzyme 2 (ACE2) was detected in the proximal tubules but not in other regions of ICR, STZ-ICR, or LPS-ICR. In LPS-STZ ACE2 was detected both in renal tubules as well as in glomeruli. The Mac-1 and podoplanin-positive cells increased in the renal parenchyma with diabetic condition and there was the distribution of a large number of Mac-1-positive cells in LPS-STZ.

Conclusions

The Pg-LPS may induce diabetic renal inflammation such as glomerulosclerosis and tubulitis with infiltration of Mac-1/podoplanin positive macrophages via glomerular overexpression of VCAM-1 and E-selectin, resulting in accumulation of both ACE2 and FGF23 which were unmetabolized with the inflammation-induced kidney damage under the diabetic condition. Periodontitis may be a critical factor in the progress of nephropathy in diabetic patients.

Presurgical naso-alveolar molding paired with cheiloplasty to treat median cleft lip deformity in holoprosencephaly

We report median cleft lip in an infant girl with lobar-typed holoprosencephaly who underwent presurgical naso-alveolar molding and subsequent cheiloplasty. At seven months postoperatively, we observed an upper lip with natural cupid-bow-shape formed with a nasal dome and two nostrils separated with reconstructed columella, which were maintained for eight years.

Maxillofacial morphological factors related to acceleration of maxillary growth attributed to facial mask treatment: a structural superimposition study

Background

Anatomical textbooks mention that the contact between the pterygoid process and the palatine’s pyramidal process is not a “suture” but “conjugation.”.The aim was to evaluate the maxillofacial morphological factor responding most to the orthopedic force of facial mask treatment, using the structural superimposition analysis.

Methods

Thirty-one girls with Angle Class III malocclusion treated using a facial mask (FM group) and 11 girls with pseudo-Class III malocclusion (pseudo-III group) were examined. Lateral cephalograms at pre- and posttreatment were analyzed to evaluate maxillofacial changes. Cephalometric structural superimposition analysis originating with Björk and Skieller was also performed.

Results

In the FM group, a multiple linear regression model showed that maxillary sutural growth was significantly associated with counter-clockwise rotation of the maxilla and treatment changes in the anteroposterior distance from the pterygomaxillary fissure to the maxillary anterior alveolus, not changes in the distance from the nasion to the maxillary anterior alveolus.

Conclusions

Structural superimposition analysis showed that counter-clockwise rotation of the maxilla and changes in the distance from the pterygomaxillary fissure to the maxillary anterior alveolus responded most to the orthopedic force of facial mask treatment. The analysis implicated that the pterygoid fissure–palatine’s pyramidal process conjugation responds most to facial mask treatment among maxillofacial sutures and conjugation, and that the difference in the response induces maxillary counter-clockwise rotation.

Electronic supplementary material

The online version of this article (10.1186/s40510-018-0254-9) contains supplementary material, which is available to authorized users.

TRPV2 channel inhibitors attenuate fibroblast differentiation and contraction mediated by keratinocyte-derived TGF-β1 in an in vitro wound healing model of rats

BACKGROUND

Keratinocytes release several factors that are involved in wound contracture and scar formation. We previously reported that a three-dimensional reconstruction model derived from rat skin represents a good wound healing model.

OBJECTIVE

We characterized the role of transient receptor potential (TRP) channels in the release of transforming growth factor (TGF)-β1 from keratinocytes and the differentiation of fibroblasts to identify possible promising pharmacological approaches to prevent scar formation and contractures.

METHODS

The three-dimensional culture model was made from rat keratinocytes seeded on a collagen gel in which dermal fibroblasts had been embedded.

RESULTS

Among the TRP channel inhibitors tested, the TRPV2 inhibitors SKF96365 and tranilast attenuated most potently keratinocyte-dependent and - independent collagen gel contraction due to TGF-β signaling as well as TGF-β1 release from keratinocytes and α-smooth muscle actin production in myofibroblasts. Besides the low amounts detected in normal dermis, TRPV2 mRNA and protein levels were increased after fibroblasts were embedded in the gel. TRPV2 was also expressed in the epidermis and keratinocyte layers of the model. Both inhibitors and TRPV2 siRNA attenuated the intracellular increase of Ca²⁺ induced by the TRPV agonist 2-aminoethoxydiphenyl borate in TGF-β1-pretreated fibroblasts.

CONCLUSION

This is the first study to show that compounds targeting TRPV2 channels ameliorate wound contraction through the inhibition of TGF-β1 release and the differentiation of dermal fibroblasts in a culture model.

The promotion of nephropathy by Porphyromonas gingivalis lipopolysaccharide via toll-like receptors

BACKGROUND

Recently, we reported that toll-like receptor (TLR)2 and TLR4 localized on the glomerular endothelium in the glomeruli of streptozotocin (STZ)-induced type 1 diabetic mice and high fat diet feed-induced type 2 diabetic mice, and that periodontal pathogen Porphyromonas gingivalis LPS (Pg-LPS) administration lowered the survival rate of diabetic mice. The present study aims to examine the effect of TLR4 blocking on the suppression of Pg-LPS-induced diabetic nephropathy.

METHODS

The survival rate and morphological/biochemical features for streptozotocin-induced diabetic mice with Pg-LPS and TLR4 blocker eritoran administration were investigated by reporter gene assay, urine and blood analysis, immunohistochemistry, and real time-PCR.

RESULTS AND CONCLUSIONS

All of the diabetic mice administered Pg-LPS were euthanized within the survival period of almost all of the diabetic mice. The blood urea nitrogen and creatinine, expression of TLR2 and TGF-b, and type 1 collagen accumulation, in the diabetic mice increased significantly with the Pg-LPS administration. In spite of the limited TLR4 activation with Pg-LPS, the TLR4 blocker eritoran decreased blood urea nitrogen and creatinine, and raised the survival rate of the Pg-LPS-administered diabetic mice slightly. The high expression levels of TLR2, TGF-b, and type 1 collagen in Pg-LPS-administered diabetic mice decreased with eritoran. Nuclear STAT3 which enhances TLR2 expression was detected in the TLR2-expressing glomeruli of diabetic mice. The TLR2 and STAT3 gene expression increased by the Pg-LPS administration but decreased with eritoran. These may suggest that Pg-LPS-induced diabetic nephropathy is mainly dependent on TLR2 signaling on glomerular endothelial cells, and that TLR4 blocker eritoran may play a role to slow the progress of diabetic nephropathy.

Quantitative evaluation of myofibroblast apoptosis during wound healing in rat palate after post-operative administration of basic fibroblast growth factor (bFGF)

OBJECTIVE

Excessive wound contraction apparently inhibits maxillary growth; thus, myofibroblast apoptosis needs to be accelerated in mucoperiosteal denudation after palatoplasty. The aim of this study was to evaluate myofibroblast apoptosis during wound healing in mucoperiosteal denudation of rat palates immediately after post-operative administration of basic fibroblast growth factor (bFGF).

MATERIALS AND METHODS

A total of 100 male Wistar rats aged 20 days were divided into control, scar, sham and bFGF groups (n = 25 each). In the scar, sham and bFGF groups, mucoperiosteum was removed from the palate and fibrin glue was applied to the exposed bone surface immediately after surgery. In the bFGF group, 10 μL of 2 μg/μL bFGF solution was injected into the operated area beneath the fibrin glue. At 2, 5, 7, 14 and 28 days post-operatively, myofibroblast apoptosis during the wound healing process was investigated by double immunofluorescence staining. The apoptotic area of myofibroblasts was measured using image software.

RESULTS

In the bFGF group, at 2 days, apoptosis of myofibroblasts in the lamina propria and submucosa was marked, as compared with the other three groups and apoptosis of myofibroblasts was scarcely seen at 5 days. At 5 and 7 days, the apoptotic area of myofibroblasts in the bFGF group was statistically significantly smaller when compared to the scar and sham groups.

CONCLUSION

The results confirmed that bFGF injection immediately after surgery accelerated apoptosis of myofibroblasts in mucoperiosteal denudation of rats. This may reduce maxillary growth retardation due to excessive wound contraction.

Oxygen saturation and electromyographic changes in masseter muscle during experimental chewing of gum with harder texture

OBJECTIVE

The purpose of this study was to clarify the relationship between changes in masseter muscle oxygenation measured by near-infrared spectroscopy (NIRS) and changes in the electromyographic (EMG) power spectrum during experimental chewing of gum with harder texture, to improve the understanding of the use of NIRS in assessing masseter muscle fatigue.

MATERIAL AND METHODS

Ten female volunteers with normal occlusion were examined. Mean age (standard deviation) was 28.4 (3.8) years. Mean fracture stress of gum was 12.5 × 10(4) N/m(2). Subjects were instructed to chew gum for 60 s (75 strokes) on the voluntary chewing side at a pace of 1.25 strokes/s. Simultaneous recordings of NIRS and EMG signals from masseter muscle were performed during gum chewing.

RESULTS

Oxygen saturation levels decreased from the start of chewing, then stabilized with a break point between the two phases. The normalized EMG amplitude increased and the mean frequency of the EMG power spectrum decreased during gum chewing. The timing of break point appearance was related to the timing of a significant decrease in median frequency, but no clear relationships were found between break point appearance and increased EMG amplitude.

CONCLUSIONS

These results suggest that the break point of the oxygen saturation curve, as obtained from NIRS measurements, could be used as an indicator of masseter muscle fatigue as assessed by a shift in the EMG power spectrum to lower frequencies.

Characterization of the interaction of TZT-1027, a potent antitumor agent, with tubulin

TZT-1027, a derivative of dolastatin 10 isolated from the Indian Ocean sea hare Dolabella auricularia in 1987 by Pettit et al., is a potent antimicrotubule agent. We have compared the activity of TZT-1027 with that of dolastatin 10 as well as the vinca alkaloids vinblastine (VLB), vincristine (VCR) and vindesine (VDS). TZT-1027 and dolastatin 10 inhibited microtubule polymerization concentration-dependently at 1 - 100 microM with IC50 values of 2.2 +/- 0.6 and 2.3 +/- 0.7 microM, respectively. VLB, VCR and VDS inhibited microtubule polymerization at 1 - 3 microM with IC50 values of 2.7 +/- 0.6, 1.6 +/- 0.4 and 1.6 +/- 0.2 microM, respectively, but showed a slight decrease in inhibitory effect at concentrations of 10 microM or more. TZT-1027 also inhibited monosodium glutamate-induced tubulin polymerization concentration-dependently at 0.3 - 10 microM, with an IC50 of 1.2 microM, whereas VLB was only effective at 0.3 - 3 microM, with an IC50 of 0.6 microM, and caused so-called "aggregation" of tubulin at 10 microM. Scatchard analysis of the binding data for [(3)H]VLB suggested one binding site (Kd 0.2 +/- 0.04 microM and Bmax 6.0 +/- 0.26 nM / mg protein), while that for [(3)H]TZT-1027 suggested two binding sites, one of high affinity (Kd 0.2 +/- 0.01 microM and Bmax 1.7 +/- 0.012 nM / mg protein) and the other of low affinity (Kd 10. 3 +/- 1.46 microM and Bmax 11.6 +/- 0.83 nM / mg protein). [(3)H]TZT-1027 was completely displaced by dolastatin 10 but only incompletely by VLB. [(3)H]VLB was completely displaced by dolastatin 10 and TZT-1027. Furthermore, TZT-1027 prevented [(3)H]VLB from binding to tubulin in a non-competitive manner according to Lineweaver-Burk analysis. TZT-1027 concentration-dependently inhibited both [(3)H]guanosine 5'-triphosphate (GTP) binding to and GTP hydrolysis on tubulin. VLB inhibited the hydrolysis of GTP on tubulin concentration-dependently to a lesser extent than TZT-1027, but no inhibitory effect of VLB on [(3)H]GTP binding to tubulin was evident even at 100 microM. Thus, TZT-1027 affected the binding of VLB to tubulin, but its binding site was not completely identical to that of VLB. TZT-1027 had a potent inhibitory effect on tubulin polymerization and differed from vinca alkaloids in its mode of action against tubulin polymerization.

ATZ1993, an orally active and novel nonpeptide antagonist for endothelin receptors and inhibition of intimal hyperplasia after balloon denudation of the rabbit carotid artery

The present experiments were designed to investigate the effect of ATZ1993 [3-carboxy-4,5-dihydro-1-[1-(3-ethoxyphenyl)propyl]-7-(5-pyrimidinyl)met hoxy-[1H]-benz[g]indazole] on the intimal hyperplasia after balloon endothelial denudation of the rabbit carotid artery. ATZ1993 inhibited the specific [125I]endothelin (ET)-1 binding not only to ET-receptor subtype A (ET(A)) with a pKi value of 8.69+/-0.02, but also to ET-receptor subtype B (ET(B)) with a pKi value of 7.20+/-0.03. Counterscreening in the binding assay (30 different receptors) confirmed that ATZ1993 had a high selectivity for ET receptors. Increases in intima:media ratio and DNA content in the vessel wall were significantly (P < 0.005) inhibited by ATZ1993 in a daily dose of 30 mg x 200 ml(-1) x kg(-1) for 1 week before and 6 weeks after balloon denudation. Inhibition of the intimal hyperplasia with ATZ1993 was determined as approximately 77% for increases in intima:media ratio and DNA content. Plasma concentrations of ATZ1993 ranged between 121.6+/-26.6 and 131.7+/-20.9 nM throughout experimental periods. Mean arterial blood pressure, heart rate and body weight gain remained unaffected by administering ATZ1993. These results demonstrate that ATZ1993 is a novel nonpeptide and nonselective ET(A)/ET(B)-receptor antagonist, and the agent when administered orally inhibits effectively intimal hyperplasia after balloon denudation of the rabbit carotid artery.

Gestational changes in endothelin-1-induced receptors and myometrial contractions in rat

The present experiments were performed to characterize the gestational changes in endothelin (ET)-1-induced myometrial contractions and ET receptors in rat. ET-1-induced contractions were composed of two types: increases in resting tone and rhythmic contractions. The increase in resting tone was decreased at 7 days of gestation, but increased at 20 days. The increase in amplitude and frequency of rhythmic contractions remained unchanged during days 7-14 of gestation. Continuous rhythmic contractions were not produced by ET-1 near the term. Both contractions were inhibited by the antagonists BQ 123 and Ro 46-2005 but not by RES 701-1 or BQ 788. In binding studies, total binding sites of [1251]-ET-1 were unchanged, however higher affinity binding sites appeared during pregnancy in addition to the lower affinity sites. The specific [125I]-ET-1 binding in non-pregnant and pregnant myometrium was completely inhibited by unlabelled ET-1 and Ro 46-2005. In contrast, the proportion which was inhibited by BQ 123 was decreased during pregnancy. In conclusion, characteristic gestational changes were the augmentation of ET-1-induced increased resting tone near term, and the appearance of high affinity ET-1 binding sites and an increase in BQ 123-resistant ET-1 binding sites during pregnancy. Further investigations are needed to understand the physiological role of these changes.

Endogenous asymmetrical dimethylarginine and hypertension associated with puromycin nephrosis in the rat

1. The present experiments were designed to investigate the role of asymmetrical NG,NG-dimethyl-L-arginine (ADMA) in causing hypertension associated with the focal and segmental glomerulosclerosis (FSGS) produced by a single bolus of puromycin aminonucleoside (PAN) and successive injection of protamine for 7 days in rats which had undergone unilateral nephrectomy. 2. After the unilateral nephrectomy, and administering PAN and protamine, histological examinations of the kidney revealed a typical FSGS, that is, evident abnormalities including segmental mesangial proliferation, obliteration of glomerular capillary lumens and adhesions between the glomerulus and Bowman's capsule could be observed. Changes in the glomerular epithelial cells consisted of the swelling with bleb formation. 3. In the FSGS rats, urine volume and urinary protein were significantly (P<0.05 and P<0.005) increased throughout 4-week experimental period, while the creatinine clearance was significantly (P<0.005) and transiently decreased, and recovered 4 weeks later. These changes were associated with the sustained elevation of the systolic blood pressure. 4. ADMA levels in aortic endothelial cells, plasma and urine were significantly (P<0.05 and P<0.005) increased in the FSGS rats, but the level in the kidney remained unchanged. 5. The basal level and net production of cyclic GMP in the aortic vessel wall with endothelium when stimulated by norepinephrine and acetylcholine were significantly (P<0.05 and P<0.01) attenuated in the FSGS rats. 6. There were significant and positive correlations between systolic blood pressure (y) and ADMA levels (x) in endothelial cells (y=4.43x+122.2, r=0.979, P<0.0001), plasma (y=0.10x+71.9, r=0.921, P<0.001) and urine (y=0.48x+126.9, r =0.699, P<0.005), but not significant in the kidney (y=0.06x+102.7, r=0.252, NS). 7. These findings suggest that ADMA as an endogenous inhibitor of NO synthesis may play an important role for the pathogenesis in the hypertension associated with the experimental FSGS in the rat.

M3-type muscarinic receptors predominantly mediate neurogenic quick contraction of bovine ciliary muscle

1. The present experiments were designed to investigate which subtypes of muscarinic receptors are involved in the neurogenic quick contraction of bovine ciliary muscle in connection to quick eye focal accommodation. 2. Transmural electrical stimulation (TES) produced a transient contraction, which was abolished in the presence of 3 x 10(-7) M tetrodotoxin and 10(-6) M atropine, but greatly augmented by 3 x 10(-7) M physostigmine. 3. The exogenously applied acetylcholine (ACh: 10(-9) to 3 x 10(-6) M) produced a concentration-dependent contraction, which was competitively antagonized by 10(-6) M atropine and augmented by 3 x 10(-7) M physostigmine, but unaffected by 3 x 10(-7) M tetrodotoxin. 4. The magnitude and time to peak of the maximal contraction produced by TES were significantly greater (1267.5 +/- 86.0 mg, P < 0.005) and shorter (9.0 +/- 0.2 sec, P < 0.005) than corresponding values (97.0 +/- 9.9 mg and 20.3 +/- 2.1 sec, respectively) of the phasic contraction caused by exogenously applied 10(-5) M ACh, at which concentration the agonist caused the maximal contraction. The velocity (140.6 +/- 7.8 mg/sec) of the transient contraction caused by TES was approximately 28-fold greater than that of the phasic contraction caused by ACh (5.1 +/- 0.9 mg/sec). 5. The contractions produced by TES were greatly attenuated by 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) as an M3 antagonist and slightly by pirenzepine as an M1 antagonist (20.2 +/- 7.9% inhibition at the highest concentration), but not by methoctramine (MET) as an M2 antagonist. The IC50 value (-log M) for 4-DAMP was determined to be 7.17 +/- 0.14. 6. Scatchard plot analysis of [3H]-quinuclidinylbenzilate (QNB) binding revealed that the binding sites constituted a single population with a Kd of 31.2 +/- 0.8 pM and a Bmax of 895.5 +/- 93.2 fmol/mg protein. The activity in inhibiting [3H]-QNB binding was most potent with 4-DAMP (-log Ki = 7.98 +/- 0.02), but less potent with pirenzepine (-log Ki = 6.43 +/- 0.04) and MET (-log Ki = 7.32 +/- 0.16). 4-DAMP was approximately 35- and 5-fold more potent than pirenzepine and MET in terms of -log Ki values, respectively, suggesting the predominant localization of M3 receptor subtypes in the bovine ciliary muscle membrane. 7. These results suggest that TES produces a neurogenic quick contraction of the bovine ciliary muscle, which would be mediated mainly by ACh released from the intramural nerve terminals and subsequent excitation of M3 receptor subtypes localized on the ciliary muscle cells, and that neurogenic quick contraction of the ciliary muscle is possibly involved in part in eye focal accommodation.

Nitric oxide-induced ciliary muscle relaxation during contraction with endothelin-1 is mediated through elevation of cyclic GMP

PURPOSE

Nitric oxide (NO) relaxes ciliary smooth muscle, and endothelin-1 (ET-1) is reported to regulate ciliary muscle tone. Despite the physiological significance of nitric oxide and ET-1, very few studies have attempted to characterize the mutual modes of action of these mediators in this tissue. Thus, the present experiments were designed to investigate a possible relaxation mechanism of nitric oxide in bovine ciliary muscle that has been contracted by ET-1.

METHODS

The effects of sodium nitroprusside (SNP), as a nitric oxide donor, methylene blue, as an inhibitor of guanylate cyclase, and 8-bromo-cyclic GMP on the bovine ciliary muscle contracted with ET-1 were examined. The changes in cyclic GMP level and relaxation, in response to SNP alone or in combination with 3-isobutyl-1-methylxanthine (IBMX) as a nonselective inhibitor of phosphodiesterases, were also determined.

RESULTS

Sodium nitroprusside (SNP) produced a concentration-dependent relaxation, which was significantly (p < 0.005) augmented by 10(-5) M 3-isobutyl-1-methylxanthine (IBMX) and significantly (p < 0.005) attenuated by 3 x 10(-5) M methylene blue as an inhibitor of guanylate cyclase. The relaxation in response to SNP was accompanied by an increase in the cyclic 3':5' guanosine monophosphate (cyclic GMP) level, which was again significantly (p < 0.05) augmented by 10(-5) M IBMX and significantly (p < 0.005) attenuated by 3 x 10(-5) M methylene blue. The exogenously applied 8-bromo-cyclic GMP relaxed the ciliary muscle strips during the contraction caused by ET-1.

CONCLUSIONS

These results lead us to assume that NO generated from SNP is closely related to cyclic GMP production via the activation of guanylate cyclase and, in turn, causes a relaxation response in the bovine ciliary muscle contracted with ET-1.

Effect of nicotine on the intimal hyperplasia after endothelial removal of the rabbit carotid artery

1. The present experiments were designed to investigate the effect of long-term oral nicotine (10 mg/200 ml/kg/day for 7 weeks) on the intimal hyperplasia after endothelial removal of the rabbit carotid artery. 2. The plasma concentrations of nicotine were determined to be 11.7-12.5 ng/ml during the term of administration and corresponded to the plasma levels in human smokers. 3. Six weeks after the endothelial removal, light microscopy revealed a marked intimal hyperplasia. Administration of nicotine tended to accelerate the intimal hyperplasia, which was estimated by comparing the histological findings, DNA content and wet weight of the vessel wall. 4. Acetylcholine- and A23187-induced endothelium-dependent relaxations were greatly impaired in the hyperplastic artery strips. The impairment of relaxations tended to be accelerated in the nicotine group. Sodium nitroprusside-induced relaxation was not different between the control and the hyperplastic artery strips and remained unaffected in the nicotine group. 5. The concentrations of endogenous nitric oxide (NO) synthesis inhibitors, NG-monomethyl-L-arginine (L-NMMA) and asymmetrical NG,NG-dimethyl-L-arginine (ADMA) were significantly more increased in the regenerated endothelial cells compared with those in the control endothelial cells. The concentrations of L-NMMA and ADMA in the regenerated endothelial cells were significantly increased by as much as 1.3 x 10(-6) and 5.6 x 10(-7) M, respectively, in the nicotine group. 6. Immunoreactive endothelin-1 was significantly increased in the hyperplastic vessel wall (2.4 times that of the control) in 6 weeks. Administration of nicotine tended to increase the level. 7. It seems possible to assume from these results that, although, under the present experimental conditions, nicotine exhibited a tendency to accelerate the intimal hyperplasia after endothelial removal, the longer exposure to nicotine or a higher dose of the agent or both would significantly accelerate the intimal hyperplasia through the enhanced impairment of endothelium-derived relaxing factor/ NO production, which might be brought about by the enhanced increases in L-NMMA and ADMA concentrations, and the enhanced increase in endothelin-1 in the vessel wall.

Antitumor activity of TZT-1027, a novel dolastatin 10 derivative

Dolastatin 10, a pentapeptide isolated from the marine mollusk Dolabella auricularia, has antitumor activity. TZT-1027, a dolastatin 10 derivative, is a newly synthesized antitumor compound. We evaluated its antitumor activity against a variety of transplantable tumors in mice. Intermittent injections of TZT-1027 were more effective than single or repeated injections in mice with P388 leukemia and B16 melanoma. Consequently, TZT-1027 shows schedule dependency. TZT-1027 was effective against P388 leukemia not only when administered i.p., but also when given i.v. However, although TZT-1027 given i.v. was active against murine solid tumors, TZT-1027 administered i.p. was ineffective against all the tumors tested with the exception of colon 26 adenocarcinoma. The i.v. injection of TZT-1027 at a dose of 2.0 mg/kg remarkably inhibited the growth of three murine solid tumors; colon 26 adenocarcinoma, B16 melanoma and M5076 sarcoma, with T/C values of less than 6%. The antitumor activities of TZT-1027 against these tumors were superior or comparable to those of the reference agents; dolastatin 10, cisplatin, vincristine, 5-fluorouracil (5-FU) and E7010. In experiments with drug-resistant P388 leukemia, TZT-1027 showed good activity against cisplatin-resistant P388 and moderate activity against vincristine- and 5-fluorouracil-resistant P388, but no activity against adriamycin-resistant P388. TZT-1027 was also effective against human xenografts, that is, tumor regression was observed in mice bearing MX-1 breast and LX-1 lung carcinomas. TZT-1027 at 10 microM almost completely inhibited the assembly of porcine brain microtubules. Therefore, its mechanism of antitumor action seems to be, at least in part, ascribable to the inhibition of microtubule assembly. Because of its good preclinical activity, TZT-1027 has been entered into phase I clinical trials.

Influence of transient global cerebral ischemia on the facilitatory modulation of the vagal baroreflex in dogs

The influence of 5-min global cerebral ischemia on the facilitatory modulation of the vagal baroreflex through central alpha 2-adrenoceptors or by the electrical stimulation of the septum was investigated in anesthetized dogs. Reflex bradycardia was produced by a bolus injection of phenylephrine at a dose which produces about a 25-mmHg increase in mean blood pressure. The ischemia was produced by the occlusion of the brachiocephalic and the left subclavian arteries with preceding ligation of the intercostal arteries. Clonidine at 10 micrograms, administered intracisternally, decreased the blood pressure and heart rate and facilitated the vagal reflex bradycardia. During the reperfusion period following ischemia, however, clonidine failed to affect the reflex bradycardia. Electrical stimulation of the septal region facilitated the reflex bradycardia without marked influences on the basal blood pressure and heart rate. The facilitatory effect was dependent on the frequency (10 to 75 Hz) and amplitude (3 to 15 V) of stimulation and was not observed after vagotomy or ischemic insult. These results suggest that 5-min global cerebral ischemia may produce the dysfunction of the neurons which are closely related to the baroreflex loop and receive the facilitatory modulation through alpha 2-adrenoceptors and/or from the forebrain structures, leading to the dysfunction of the vagal baroreflex.

Blockade of alpha 2-adrenoceptors protects the vagal baroreflex system from transient global cerebral ischemia in dogs

Ifenprodil, phentolamine, yohimbine or idazoxan, 1 mg/kg i.v., administered 5 min prior to 5-min global cerebral ischemia, completely prevented the post-ischemic dysfunction of the vagal baroreflex in anesthetized dogs. Idazoxan, 0.1 mg/kg i.v., was cerebroprotective against mild ischemia, but ineffective against severe ischemia. The post-ischemic administration of idazoxan, 1 mg/kg i.v., failed to restore the damaged vagal baroreflex. These results suggest that blockade of alpha 2-adrenoceptors during ischemia and the early reperfusion period may protect the vagal component of baroreflex from cerebral ischemia.

MK-801 prevents the post-ischemic cerebral hypoperfusion, but not the dysfunction of the vagal baroreflex in dogs

Pretreatment with MK-801, a non-competitive N-methyl-D-aspartate (NMDA) antagonist, failed to protect the vagal component of reflex bradycardia from 5-min global cerebral ischemia in dogs under pentobarbital anesthesia. On the other hand, MK-801 completely prevented the development of the post-ischemic cerebral hypoperfusion without affecting the cerebral blood flow in sham-operated animals. The results suggest that NMDA receptors may participate in the development of the secondary disturbance of the cerebral circulation, but are not involved in the post-ischemic dysfunction of the baroreflex system.