Hypophosphatasia: Evaluation of Size and Mineral Density of Exfoliated Teeth.

OBJECTIVE: Most cases of hypophosphatasia (HPP) exhibit early loss of primary teeth. Results of micro-computed tomography (micro-CT) analysis of teeth with HPP have not yet been reported. The purpose of the present study was to describe the size and mineral density distribution and mapping of exfoliated teeth with HPP using micro CT. STUDY DESIGN: Seven exfoliated teeth were obtained from a patient with HPP. Exfoliated teeth sizes were measured on micro CT images and mineral densities of the mandibular primary central incisors were determined. RESULTS: Partial dentures were fabricated for the patient to replace the eight primary teeth which had exfoliated. Most primary teeth sizes were within the normal range. The mean values of enamel and dentin mineral densities in teeth with HPP were 1.35 and 0.88 g/cm3, respectively, in the mandibular primary central incisors. CONCLUSION: Mineral density distribution and mapping revealed that the values in teeth with HPP were lower than the homonymous teeth controls in all regions from the crown to apex. Furthermore, it was demonstrated that the differences between HPP and controls were larger on the crown side and the differences tended to converge on the apex side. These results suggested that the present patient showed mild hypomineralization in the primary dentition.

Clinical relevance of Küttner tumour and IgG4-related dacryoadenitis and sialoadenitis.

OBJECTIVES: Küttner tumour (KT), so-called chronic sclerosing sialoadenitis, is characterised by concomitant swelling of the submandibular glands secondary to strong lymphocytic infiltration and fibrosis independent of sialolith formation. However, recent studies have indicated that some patients with KT develop high serum levels of IgG4 and infiltration of IgG4-positive plasma cells, namely IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS), so-called Mikulicz's disease. The aim of this study was to clarify the clinical and pathological associations between KT and IgG4-DS. MATERIALS AND METHODS: Fifty-four patients pathologically diagnosed with KT or chronic sialoadenitis were divided into two groups according to the presence or absence of sialolith (KT-S (+) or KT-S (-), respectively). RESULTS: There were no significant differences in the clinical findings, including the mean age, sex and disease duration, between the two groups. All patients in the KT-S (+) group showed unilateral swelling without infiltration of IgG4-positive plasma cells or a history of other IgG4-related diseases (IgG4-RD), while those in the KT-S (-) group showed bilateral swelling (37.5%), strong infiltration of IgG4-positive plasma cells (87.5%) and a history of other IgG4-RD (12.5%). CONCLUSIONS: These results suggest an association between the pathogeneses of KT-S (-) and IgG4-DS, but not KT-S (+).

Self-Esteem and Oral Condition of Institutionalized Abused Children in Japan.

OBJECTIVE: Abused children have been reported to have low self-esteem. The aim of this study was to investigate the effects of dental intervention on self-esteem, oral condition, and concern for oral health in abused children admitted to a child protection service facility. STUDY DESIGN: We examined the oral condition of 65 children (34 boys, 31 girls; aged 2-15 years), instructed them in tooth-brushing. Self-esteem was examined using Pope's five-scale test for children. Before discharge, the children completed questionnaires on concern about their oral health. RESULTS: The findings revealed the reasons for admission were child abuse and neglect (n=45), domestic violence against the mother (n= 20), special needs (n=11), delinquency (n=7), school refusal (n=2), and other reasons (n=3). Thirty-five of the 65 residents (54%) needed treatment for caries. Of these, 24 (69%) were abused children and 11 (31%) were admitted due to other reasons. Mean self-esteem score differed significantly between the resident children (n=43) and an outpatient control group (n=102) (59.16±14.54 vs 73.92±16.81, respectively; p<0.01). CONCLUSION: Although the abused children had low self-esteem, after dental intervention, positive answers regarding oral health were obtained. The findings suggest that dental interventions might be effective for helping to improve the self-esteem of abused children.

Prediction of nodal metastasis based on intraoral sonographic findings of the primary lesion in early-stage tongue cancer.

The aim of this study was to clarify the correlation between imaging findings obtained using intraoral ultrasonography (US) and pathological findings of tongue cancers, and to examine the predictive value of intraoral US findings with respect to occult nodal metastasis. This was a retrospective study based on the medical records of 123 patients with T1-2N0 tongue cancer. The depth of invasion (DOI) on intraoral US was positively correlated with the pathological invasion depth (PID) (ρ = 0.7080, P < 0.0001). Receiver operating characteristic analyses revealed an optimal DOI cut-off value of 4.1 mm and optimal PID cut-off value of 3.9 mm to detect nodal metastasis. Regarding the margin shape of the primary tumour on intraoral US, the incidence of nodal metastasis was significantly higher for the permeated type than for the pressure type (P < 0.001) and wedge-shaped type (P = 0.002). Furthermore, tumours with peritumoural vascularity assessed by power Doppler US had a significantly higher incidence of nodal metastasis than tumours without (P = 0.003). The sensitivity, specificity, and accuracy of the permeated type to predict nodal metastasis was 53.6%, 95.8%, and 86.2%, respectively. These results suggest that intraoral US findings closely reflect pathological findings and could be useful to predict occult nodal metastasis in patients with early-stage tongue cancer.

Isolation of a thermotolerant bacterium producing medium-chain-length polyhydroxyalkanoate.

AIMS: The aim of this study was to isolate a thermotolerant micro-organism that produces polyhydroxyalkanoates (PHAs) composed of medium-chain-length (mcl) HA units from a biodiesel fuel (BDF) by-product as a carbon source. METHODS AND RESULTS: We successfully isolated a thermotolerant micro-organism, strain SG4502, capable to accumulate mcl-PHA from a BDF by-product as a carbon source at a cultivation temperature of 45°C. The strain could also produce mcl-PHA from acetate, octanoate and dodecanoate as sole carbon sources at cultivation temperatures up to 55°C. Taxonomic studies and 16S rRNA gene sequence analysis revealed that strain SG4502 was phylogenetically affiliated with species of the genus Pseudomonas. This study is the first report of PHA synthesis by a thermotolerant Pseudomonas. CONCLUSIONS: A novel thermotolerant bacterium capable to accumulate mcl-PHA from a BDF by-product was successfully isolated. SIGNIFICANCE AND IMPACT OF THE STUDY: A major issue regarding industrial production of microbial PHAs is their much higher production cost compared with conventional petrochemical-based plastic materials. Especially significant are the cost of a fermentative substrate and the running cost to maintain a temperature suitable for microbial growth. Thus, strain SG4502, isolated in this study, which assimilates BDF by-product and produces PHA at high temperature, would be very useful for practical application in industry.

Elevated expression of protease-activated receptor 1 via ΔNp63 down-regulation contributes to nodal metastasis in oral squamous cell carcinoma.

Protease-activated receptor 1 (PAR1) is known as a thrombin receptor. Recent studies have reported PAR1 expression in various malignancies; however, its role in oral squamous cell carcinoma (OSCC) requires clarification. A previous study showed that down-regulation of ΔNp63, a homolog of p53, augments PAR1 expression in OSCC. In the present study, the association of PAR1 expression with clinicopathological findings in OSCC was examined retrospectively. Expression of PAR1, thrombin, and ΔNp63 was examined immunohistochemically in OSCC specimens. Patients were divided into three groups based on the expression pattern of PAR1 at the invasive front: group A, PAR1-negative in both cancer and stromal cells; group B, positive in stromal cells but negative in cancer cells; group C, positive in both cancer and stromal cells. Histologically high-grade tumours were significantly more common in group C. Patients in group C had the highest incidence rate of nodal metastasis (P<0.001) and a lower survival rate (P=0.085) than those in the other groups. At the invasive front, in group C, thrombin was expressed but ΔNp63 expression was weak. These results indicate that increased PAR1 expression in both cancer and stromal cells could be a useful predictive marker of nodal metastasis and that ΔNp63 is involved in regulating PAR1 expression.

Alteration of interleukin 4 production results in the inhibition of T helper type 2 cell-dominated inflammatory bowel disease in T cell receptor alpha chain-deficient mice.

T cell receptor alpha chain-deficient (TCR-alpha(-/-)) mice are known to spontaneously develop inflammatory bowel disease (IBD). The colitis that develops in these mice is associated with increased numbers of T helper cell (Th)2-type CD4(+)TCR-betabeta (CD4(+)betabeta) T cells producing predominantly interleukin (IL)-4. To investigate the role of these Th2-type CD4(+)betabeta T cells, we treated TCR-alpha(-/-) mice with anti-IL-4 monoclonal antibody (mAb). Approximately 60% of TCR-alpha(-/-) mice, including those treated with mock Ab and those left untreated, spontaneously developed IBD. However, anti-IL-4 mAb-treated mice exhibited no clinical or histological signs of IBD, and their levels of mucosal and systemic Ab responses were lower than those of mock Ab-treated mice. Although TCR-alpha(-/-) mice treated with either specific or mock Ab developed CD4(+)betabeta T cells, only those treated with anti-IL-4 mAb showed a decrease in Th2-type cytokine production at the level of mRNA and protein and an increase in interferon gamma-specific expression. These findings suggest that IL-4-producing Th2-type CD4(+)betabeta T cells play a major immunopathological role in the induction of IBD in TCR-alpha(-/-) mice, a role that anti-IL-4 mAb inhibits by causing Th2-type CD4(+)betabeta T cells to shift to the Th1 type.

Acute Deterioration of Kidney Function after Total Hip Arthroplasty.

INTRODUCTION: Post-operative acute kidney injury is a serious complication and identifying modifiable factors could assist in peri-operative management. This study aimed to identify the pre-operative and intra-operative factors associated with the incidence of post-operative acute kidney injury and acute deterioration of kidney function after total hip arthroplasty.Materials and methods: This single-center, retrospective, observational study included 203 patients who underwent unilateral primary total hip arthroplasty. Acute kidney injury was determined using biochemical markers according to the risk, injury, failure, loss of kidney function, and end-stage kidney disease (RIFLE) criteria. Acute deterioration of kidney function was defined as the reduction of estimated glomerular filtration rate by ≥10ml/min/1.73m2. RESULTS: Prior to total hip arthroplasty, 20% of all patients met the chronic renal dysfunction criterion of glomerular filtration rates <60ml/min/1.73m2 (glomerular filtration rate categories G3a-G5). Incidence rates of acute kidney injury and acute deterioration of kidney function after total hip arthroplasty were 0.49% and 6.9%, respectively. Multivariate regression analysis showed that diabetes mellitus and use of nonsteroidal anti-inflammatory drugs before total hip arthroplasty were significant risk factors for acute deterioration of kidney function. Advanced age, preoperative renal dysfunction, antihypertensive, diuretics, or statin use, operation time, total blood loss, type of anesthetic, and body mass index were not significant risk factors. CONCLUSION: Diabetes mellitus and use of nonsteroidal anti-inflammatory drugs were controllable risks, and multidisciplinary approaches are a reasonable means of minimising peri-operative acute kidney injury or acute deterioration of kidney function.

Studies on mitochondrial structure and function in Physarum polycephalum. V. Behaviour of mitochondrial nucleoids throughout mitochondrial division cycle.

The fine structure of mitochondria and mitochondrial nucleoids in exponentially growing Physarum polycephalum was studied at various periods throughout the mitochondrial division cycle by light and electron microscopy. The mitochondrial nucleoid elongates lingitudinally while the mitochondrion increases in size. When the nucleoid reaches a length of approximately 1.5 mum the mitochondrial membrane invaginates at the center of the mitochondrion and separates the mitochondrial contents. However, the nucleoid does not divide even when the mitochondrial sections are connected by a very narrow bridge. Just before division of the mitochondrion, the nucleoid divides by constriction of the limiting membrane of the dividing mitochondrion. After division, one end of the nucleoid appears to be associated with the inner mitochondrial membrane. The nucleoid then again becomes situated in the center of the mitochondrion before repeating these same processes.

Growth cone collapse and inhibition of neurite growth by Botulinum neurotoxin C1: a t-SNARE is involved in axonal growth.

The growth cone is responsible for axonal growth, where membrane expansion is most likely to occur. Several recent reports have suggested that presynaptic proteins are involved in this process; however, the molecular mechanism details are unclear. We suggest that by cleaving a presynaptic protein syntaxin, which is essential in targeting synaptic vesicles as a target SNAP receptor (t-SNARE), neurotoxin C1 of Clostridium botulinum causes growth cone collapse and inhibits axonal growth. Video-enhanced microscopic studies showed (a) that neurotoxin C1 selectively blocked the activity of the central domain (the vesicle-rich region) at the initial stage, but not the lamellipodia in the growth cone; and (b) that large vacuole formation occurred probably through the fusion of smaller vesicles from the central domain to the most distal segments of the neurite. The total surface area of the accumulated vacuoles could explain the membrane expansion of normal neurite growth. The gradual disappearance of the surface labeling by FITC-WGA on the normal growth cone, suggesting membrane addition, was inhibited by neurotoxin C1. The experiments using the peptides derived from syntaxin, essential for interaction with VAMP or alpha-SNAP, supported the results using neurotoxin C1. Our results demonstrate that syntaxin is involved in axonal growth and indicate that syntaxin may participate directly in the membrane expansion that occurs in the central domain of the growth cone, probably through association with VAMP and SNAPs, in a SNARE-like way.

Theanine, gamma-glutamylethylamide, a unique amino acid in tea leaves, modulates neurotransmitter concentrations in the brain striatum interstitium in conscious rats.

Theanine (gamma-glutamylethylamide) is one of the major amino acid components in green tea and can pass through the blood-brain barrier. Recent studies suggest that theanine affects the mammalian central nervous system; however, the detailed mechanism remains unclear. In this study, we demonstrated the effect of theanine on neurotransmission in the brain striatum by in vivo brain microdialysis. Theanine injection into the rat brain striatum did not increase the concentration of excitatory neurotransmitters in the perfusate. On the other hand, theanine injection increased the concentration of glycine in the perfusate. Because it has been reported that theanine promotes dopamine release in the rat striatum, we investigated the glycine and dopamine concentrations in the perfusate. Co-injection of glycine receptor antagonist, strychnine, reduced theanine-induced changes in dopamine. Moreover, AMPA receptor antagonist, which regulates glycine and GABA release from glia cells, inhibited these effects of theanine and this result was in agreement with the known inhibitory effect of theanine at AMPA receptors.

Calmodulin mediates calcium-dependent inactivation of the cerebellar type 1 inositol 1,4,5-trisphosphate receptor.

The dependency of purified mouse cerebellar type 1 inositol 1,4,5-trisphosphate receptor (IP3R1)/Ca2+ channel function on cytoplasmic Ca2+ was examined. In contrast to the channels in crude systems, the purified IP3R1 reconstituted into planar lipid bilayers did not show the bell-shaped dependence on Ca2+. It was activated with increasing Ca2+ sublinearly without inhibition even up to 200 microM. The addition of calmodulin to the cytoplasmic side inhibited the channel at high Ca2+ concentrations. Calmodulin antagonists reversed the Ca2+-dependent inactivation of the native channels in cerebellar microsomes. These results indicate that the bell-shaped dependence on cytoplasmic Ca2+ is not an intrinsic property of the IP3R1, and the Ca2+-dependent inactivation is directly mediated by calmodulin.

Satisfaction with bispectral index monitoring of propofol-mediated sedation during endoscopic submucosal dissection: a prospective, randomized study.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) is one of the most complex and lengthy endoscopic procedures, so deep sedation during ESD is indispensable. Our study aims were to determine whether bispectral index (BIS) monitoring is useful in titrating and reducing the dose of the sedative propofol during ESD, and to measure the satisfaction of patients and endoscopists involved in this complex and lengthy endoscopic therapy. PATIENTS AND METHODS: We performed a prospective, randomized clinical trial from July 2006 to February 2008. A total of 156 patients, with gastric neoplasm to be treated using ESD, were randomized to two groups. The BIS group (n = 78) was monitored for propofol sedation using BIS, and the no-BIS group (n = 78) was monitored by standard methods only. The two groups were compared by evaluating the doses of propofol administered to patients and the satisfaction scores (scale of 0 - 10) of patients and endoscopists. RESULTS: Although there were no significant differences between the two groups in the mean dose of propofol used (BIS group vs. no-BIS group, 5.32 mg/kg/hour vs. 4.85 mg/kg/hour; P = 0.10), the satisfaction scores of the patients (9.15 vs. 7.94; P < 0.01) and endoscopists (8.53 vs. 6.42; P < 0.001) were significantly higher with BIS monitoring. CONCLUSIONS: Monitoring with BIS during the ESD procedure did not lead to a reduction in the dose of propofol required, but did lead to higher satisfaction scores from the patients and endoscopists. A complicated and prolonged endoscopic treatment such as ESD can be carried out with optimal safety, control, and comfort by using BIS to monitor propofol sedation.

Intra-bone marrow cotransplantation of donor mesenchymal stem cells in pig-to-NOD/SCID mouse bone marrow transplantation facilitates short-term xenogeneic hematopoietic engraftment.

We directly injected porcine donor mesenchymal stem cells (MSC) into murine bone marrow (BM) cavities to examine the effects of intra-BM cotransplantation of MSC in pig-to-NOD/SCID mouse bone marrow transplantation (BMT) on xenogeneic engraftment. Porcine MSC prepared by aspiration of iliac BM of miniature swine were identified as CD90+CD29+CD45-CD31- and shown to differentiate into osteoblastocytes and adipocytes. A few weeks after expansion, MSC (1 x 10(6) cells/mouse) were directly injected with BM cells (30 x 10(6) cells/mouse) obtained from vertebrae through a microsyringe into BM cavities of both tibiae of NOD/SCID mice after 3-Gy total body irradiation. Controls were injected with only BM cells. Porcine chimerisms of BM cells of tibiae (injection site) and of femurs (non-injection site) in recipient mice were evaluated with porcine and murine cell markers using FACS. The chimerism of porcine class I+ cells at the injection site in the MSC group and the controls were 3.45%, 1.43%, and 0.17%, and 2.27%, 0.81%, and 0.1% at 1, 3, and 6 weeks, respectively. The chimerism at the noninjection site in the MSC group and the controls were 0.21%, 1.34%, and 0.11%, and 0.06%, 0.42%, and 0.09% at 1, 3, and 6 weeks, respectively. The total chimerisms of injection site in the MSC group to 6 weeks were significantly higher than those in the control group (1.60% vs 0.99%; P < .05), whereas the chimerism of the noninjection site in MSC group was remarkably higher at 3 weeks. In conclusion, intra-BM cotransplantation of porcine donor MSC in pig-to-NOD/SCID mouse BMT improved short-term xenogeneic engraftment, presumably due to humoral factors.

Significant association of increased PD-L1 and PD-1 expression with nodal metastasis and a poor prognosis in oral squamous cell carcinoma.

Programmed cell death ligand 1 (PD-L1) and its receptor PD-1 are immune checkpoint molecules that attenuate the immune response. Blockade of PD-L1 enhances the immune response in a variety of tumours and thus serves as an effective anti-cancer treatment. However, the biological and prognostic roles of PD-L1/PD-1 signalling in oral squamous cell carcinoma (OSCC) remain to be elucidated. The purpose of this study was to examine the correlation of PD-L1/PD-1 signalling with the prognosis of OSCC patients to assess its potential therapeutic relevance. The expression of PD-L1 and of PD-1 was determined immunohistochemically in 97 patients with OSCC and the association of this expression with clinicopathological characteristics was examined. Increased expression of PD-L1 was found in 64.9% of OSCC cases and increased expression of PD-1 was found in 61.9%. Univariate and multivariate analysis revealed that increased expression of PD-L1 and PD-1 positively correlated with cervical lymph node metastasis. The expression of CD25, an activated T-cell marker, was negatively correlated with the labelling index of PD-L1 and PD-1. Moreover, the patient group with PD-L1-positive and PD-1-positive expression showed a more unfavourable prognosis than the group with PD-L1-negative and PD-1-negative expression. These data suggest that increased PD-L1 and PD-1 expression is predictive of nodal metastasis and a poor prognosis and is possibly involved in cancer progression via attenuating the immune response.

Human Papillomavirus 16 E6 Induces FoxM1B in Oral Keratinocytes through GRHL2.

High-risk human papillomavirus (HPV) is a major risk factor for oral and pharyngeal cancers (OPCs), yet the detailed mechanisms by which HPV promotes OPCs are not understood. Forkhead box M1B (FoxM1B) is an oncogene essential for cell cycle progression and tumorigenesis, and it is aberrantly overexpressed in many tumors. We previously showed that FoxM1B was the putative target of an epithelial-specific transcription factor, Grainyhead-like 2 (GRHL2). In the current study, we demonstrate that HPV type 16 (HPV-16) E6 induces FoxM1B in human oral keratinocytes (HOKs) and tonsillar epithelial cells (TECs) in part through GRHL2. FoxM1B was barely detectable in cultured normal human oral keratinocytes (NHOKs) and progressively increased in immortalized HOKs harboring HPV-16 genome (HOK-16B) and tumorigenic HOK-16B/BaP-T cells. Retroviral expression of HPV-16 E6 and/or E7 in NHOKs, TECs, and hypopharyngeal carcinoma cells (FaDu) revealed induction of FoxM1B and GRHL2 by the E6 protein but not E7. Both GRHL2 and FoxM1B were strongly induced in the epidermis of HPV-16 E6 transgenic mice and HPV+ oral squamous cell carcinomas. Ectopic expression of FoxM1B led to acquisition of transformed phenotype in HOK-16B cells. Loss of FoxM1B by lentiviral short hairpin RNA vector or chemical inhibitor led to elimination of tumorigenic characteristics of HOK-16B/BaP-T cells. Luciferase reporter assay revealed that GRHL2 directly bound and regulated the FoxM1B gene promoter activity. Using epithelial-specific Grhl2 conditional knockout mice, we exposed wild-type (WT) and Grhl2 KO mice to 4-nitroquinolin 1-oxide (4-NQO), which led to induction of FoxM1B in the tongue tissues and rampant oral tumor development in the WT mice. However, 4-NQO exposure failed to induce tongue tumors or induction of FoxM1B expression in Grhl2 KO mice. Collectively, these results indicate that HPV-16 induces FoxM1B in part through GRHL2 transcriptional activity and that elevated FoxM1B level is required for oropharyngeal cancer development.

Impaired oxygen utilization. A new mechanism for the hepatotoxicity of ethanol in sub-human primates.

The role of oxygenation in the pathogenesis of alcoholic liver injury was investigated in six baboons fed alcohol chronically and in six pair-fed controls. All animals fed alcohol developed fatty liver with, in addition, fibrosis in three. No evidence for hypoxia was found, both in the basal state and after ethanol at moderate (30 mM) or high (55 mM) levels, as shown by unchanged or even increased hepatic venous partial pressure of O2 and O2 saturation of hemoglobin in the tissue. In controls, ethanol administration resulted in enhanced O2 consumption (offset by a commitant increase in splanchnic blood flow), whereas in alcohol fed animals, there was no increase. At the moderate ethanol dose, the flow-independent O2 extraction, measured by reflectance spectroscopy on the liver surface, tended to increase in control animals only, whereas a significant decrease was observed after the high ethanol dose in the alcohol-treated baboons. This was associated with a marked shift in the mitochondrial redox level in the alcohol-fed (but not in control) baboons, with striking rises in splanchnic output of glutamic dehydrogenase and acetaldehyde, reflecting mitochondrial injury. Increased acetaldehyde, in turn, may aggravate the mitochondrial damage and exacerbate defective O2 utilization. Thus impaired O2 consumption rather than lack of O2 supply characterizes liver injury produced by high ethanol levels in baboons fed alcohol chronically.

Roles of endothelin-1 and nitric oxide in the mechanism for ethanol-induced vasoconstriction in rat liver.

This study was designed to investigate the mechanism for ethanol-induced hepatic vasoconstriction in isolated perfused rat liver. Upon initiation of ethanol infusion into the portal vein at concentrations ranging from 25 to 100 mM, portal pressure began to increase in a concentration-dependent manner and reached maximal levels in 2-5 min (initial phase), followed by a gradual decrease over the period of ethanol infusion (escape phenomenon). Endothelin-1 antiserum significantly inhibited this ethanol-induced hepatic vasoconstriction by 45-80%. Cessation of infusion of endothelin-1 antiserum was followed by a subsequent increase in portal pressure. On the other hand, when a nitric oxide synthesis inhibitor, NG-monomethyl-L-arginine (L-NMMA), was infused into the portal vein simultaneously with ethanol, the initial phase of the response of portal pressure to ethanol was not altered and the peak values of portal pressure remained unchanged. However, after the peak increase in portal pressure, the rate of decrease was less than in the absence of L-NMMA. Thus, L-NMMA diminished the escape phenomenon and sustained the vasoconstriction. This study supports the hypothesis that two endothelium-derived vasoactive factors, endothelin-1 and nitric oxide, regulate hepatic vascular tone in the presence of ethanol.

Guidance in vitro of the pollen tube to the naked embryo sac of torenia fournieri

The precise guidance of the pollen tube to the embryo sac is critical to the successful sexual reproduction of flowering plants. We demonstrate here the guidance of the pollen tube to the embryo sac in vitro by using the naked embryo sac of Torenia fournieri, which protrudes from the micropyle of the ovule. We developed a medium for culture of both the ovule and the pollen tube of T. fournieri and cocultivated them in a thin layer of solid medium. Although pollen tubes that had germinated in vitro passed naked embryo sacs, some pollen tubes that grew semi-in vitro through a cut style arrived precisely at the site of entry into the embryo sac, namely, the filiform apparatus of the synergids. When pollen tubes were unable to enter the embryo sac, they continuously grew toward the same filiform apparatus, forming narrow coils. Pollen tubes selectively arrived at complete, unfertilized embryo sacs but did not arrive at those of heat-treated ovules or those with disrupted synergids. These results convincingly demonstrate that pollen tubes are specifically attracted to the region of the filiform apparatus of living synergids in vitro.