Lung volume and collapsibility of the passive pharynx in patients with sleep-disordered breathing.

Lung volume dependence of pharyngeal airway patency suggests involvement of lung volume in pathogenesis of obstructive sleep apnea. We examined the structural interaction between passive pharyngeal airway and lung volume independent of neuromuscular factors. Static mechanical properties of the passive pharynx were compared before and during lung inflation in eight anesthetized and paralyzed patients with sleep-disordered breathing. The respiratory system volume was increased by applying negative extrathoracic pressure, thereby leaving the transpharyngeal pressure unchanged. Application of -50-cmH(2)O negative extrathoracic pressure produced an increase in lung volume of 0.72 (0.63-0.91) liter [median (25-75 percentile)], resulting in a significant reduction of velopharyngeal closing pressure of 1.22 (0.14-2.03) cmH(2)O without significantly changing collapsibility of the oropharyngeal airway. Improvement of the velopharyngeal closing pressure was directly associated with body mass index. We conclude that increase in lung volume structurally improves velopharyngeal collapsibility particularly in obese patients with sleep-disordered breathing.     

Determination of isonicotinic acid in the presence of isoniazid and acetylisoniazid Studies on isonicotinic acid formation from isoniazid in isolated rat hepatocytes

In comparison with the hepatocytes obtained from intact rats and rats pretreated with phenobarbital or 3-methylchoranthrene, the amount of isonicotinic acid (INA) formed from isoniazid (INH) increased substantially after incubation at 37°C using the pretreated hepatocytes. This suggests an oxidative pathway for INA formation from INH, apart from hydrolysis. In order to explore the exact mechanism of INA formation in the hepatocytes, an HPLC assay for INA in the presence of INH and acetylisoniazid was developed. In this assay, INA was extracted after the preparation of an ion pair with tetra-n-butylammonium hydroxide, and analysed using an ODS column and a mobile phase consisting of 0.067 M potassium dihydrogenphosphate solution-methanol (96:4 v/v). The method is simple, accurate and especially suitable for INA determination after incubation of INH in isolated rat hepatocytes.     

Immunoreactivity of VR1 on epidermal keratinocyte of human skin

We demonstrated the immunoreactivity of the receptor proteins, VR1, ion channels associated with pain sensation, on the epidermis of the human skin. Immunohistochemistry using antiserum against VR1 derived peptide showed immunoreactivity on the keratinocytes cell membrane of the human epidermis and cultured keratinocytes. The blocking peptide of the antiserum reduced the immunoreactivity on the epidermis. RT-PCR assay of cultured human keratinocyte also showed expression of VR1 mRNA. These results suggest the existence of VR1-like protein in epidermal keratinocytes of human skin.     

Formation of rhamnogalacturonan II-borate dimer in pectin determines cell wall thickness of pumpkin tissue

Boron (B) deficiency results in inhibition of pumpkin (Cucurbia moschata Duchesne) growth that is accompanied by swelling of the cell walls. Monomeric rhamnogalacturonan II (mRG-II) accounted for 80% to 90% of the total RG-II in B-deficient walls, whereas the borate ester cross-linked RG-II dimer (dRG-II-B) accounted for more than 80% of the RG-II in control plants. The results of glycosyl residue and glycosyl linkage composition analyses of the RG-II from control and B-deficient plants were similar. Thus, B deficiency does not alter the primary structure of RG-II. The addition of (10)B-enriched boric acid to B-deficient plants resulted within 5 h in the conversion of mRG-II to dRG-II-(10)B. The wall thickness of the (10)B-treated plants and control plants was similar. The formation and possible functions of a borate ester cross-linked RG-II in the cell walls are discussed.     

Octa- and nonaprenylhydroquinone sulfates, inhibitors of alpha1,3-fucosyltransferase VII, from an Australian marine sponge Sarcotragus sp

Alpha1,3-fucosyltransferase (Fuc TVII) is a key enzyme in the biosynthesis of selectin ligands. We have isolated two inhibitors of Fuc TVII from a marine sponge Sarcotragus sp. They were characterized as octa- and nonaprenylhydroquinone sulfates on the basis of spectral data. These compounds inhibited Fuc-TVII with IC50 values of 3.9 and 2.4 microg/mL, respectively.     

Effective selection system for generating marker-free transgenic plants independent of sexual crossing

 In a previous report, a novel selection protocol termed "the MAT-vector system" for generating marker-free transgenic plants (MFTPs) was presented. The first stage of the system is visual selection of morphologically abnormal transgenic shoots, ipt-shooty, that have lost apical dominance and rooting ability. The second stage involves elimination of the ipt gene and the appearance of MFTPs free of ipt gene influence. The present report describes a practical MAT-vector in which removal of the ipt gene is efficiently mediated by the site-specific recombination system R/RS from Zygosaccharomyces rouxii, in place of the maize transposable element Ac, used previously. This improved MAT-vector produced MFTPs from 39% of moderate ipt-shooty and 70% of extreme ipt-shooty lines. These results are superior to the previous MAT-vector which produced MFTPs from only 5% of ipt-shooty lines. The present novel system also induced direct development of MFTPs from adventitious buds without production of ipt-shooty intermediates. The presence of β-glucuronidase (GUS) and neomycin phosphotransferase (NPTII) genes of interest, and the absence of the ipt gene were verified by a GUS histochemical assay, NPTII assay, and molecular analysis. Received: 19 June 1998 / Revision received: 4 December 1998 / Accepted: 18 December 1998     

Effect of salt addition on the fractal structure of aggregates formed by heating dilute BSA solutions

The fractal dimension, Df, of aggregates in a dilute BSA system with added salt was evaluated by static light scattering (SLS). A fractal structure was observed for the system with NaCl addition. The values of Df increased with increasing heating time and ionic strength. The values of Df were larger than those (Df = 1.8 or 2.1) predicted by the conventional cluster-cluster aggregation model, probably due to a "restructuring" of aggregates during the aggregation process. On the other hand, a fractal structure was not apparent for the system with added CaCl2.     

The plant cell wall polysaccharide rhamnogalacturonan II self-assembles into a covalently cross-linked dimer

The location of the 1:2 borate-diol ester cross-link in the dimer of the plant cell wall polysaccharide rhamnogalacturonan II (RG-II) has been determined. The ester cross-links the apiofuranosyl residue of the 2-O-methyl-D-xylose-containing side chains in each of the subunits of the dimer. The apiofuranosyl residue in each of the two aceric acid-containing side chains is not esterified. The site of borate esterification is identical in naturally occurring and in in vitro synthesized dimer. Pb2+, La3+, and Ca2+ increase dimer formation in vitro in a concentration- and pH-dependent manner. Pb2+ is the most effective cation. The dimer accounts for 55% of the RG-II when the monomer (0.5 mM) is treated for 5 min at pH 3.5 with boric acid (1 mM) and Pb2+ (0.5 mM); at pH 5 the rate of conversion is somewhat slower. Hg2+ does not increase the rate of dimer formation. A cation's charge density and its ability to form a coordination complex with RG-II, in addition to steric factors, may regulate the rate and stability of dimer formation in vitro. Our data provide evidence that the structure of RG-II itself determines which apiofuranosyl residues are esterified with borate and that in the presence of boric acid and certain cations, two RG-II monomers self-assemble to form a dimer.     

p38alpha mitogen-activated protein kinase plays a critical role in cardiomyocyte survival but not in cardiac hypertrophic growth in response to pressure overload

The molecular mechanism for the transition from cardiac hypertrophy, an adaptive response to biomechanical stress, to heart failure is poorly understood. The mitogen-activated protein kinase p38alpha is a key component of stress response pathways in various types of cells. In this study, we attempted to explore the in vivo physiological functions of p38alpha in hearts. First, we generated mice with floxed p38alpha alleles and crossbred them with mice expressing the Cre recombinase under the control of the alpha-myosin heavy-chain promoter to obtain cardiac-specific p38alpha knockout mice. These cardiac-specific p38alpha knockout mice were born normally, developed to adulthood, were fertile, exhibited a normal life span, and displayed normal global cardiac structure and function. In response to pressure overload to the left ventricle, they developed significant levels of cardiac hypertrophy, as seen in controls, but also developed cardiac dysfunction and heart dilatation. This abnormal response to pressure overload was accompanied by massive cardiac fibrosis and the appearance of apoptotic cardiomyocytes. These results demonstrate that p38alpha plays a critical role in the cardiomyocyte survival pathway in response to pressure overload, while cardiac hypertrophic growth is unaffected despite its dramatic down-regulation.     

Changes in receptor activator of nuclear factor-kappaB, and its ligand, osteoprotegerin, bone-type alkaline phosphatase, and tartrate-resistant acid phosphatase in ovariectomized rats

We investigated time-course changes in the expression of receptor activator of nuclear factor-kappaB (RANK), its ligand (RANKL), osteoprotegerin (OPG), bone-type alkaline phosphatase (BAP), and tartrate-resistant acid phosphatase (TRAP) in ovariectomized (OVX) rats. Samples of sera and coccyges were used for analysis of the enzyme activities and expression levels of proteins and mRNAs, and an immunohistochemical analysis was also performed. Serum BAP activity increased to 158.6% of the pre-operation value at 1 week after OVX, and then decreased to 38.7% at 8 weeks after OVX. On the other hand, the serum TRAP activity increased to 130.9% of the pre-operation level at 1 week after OVX, and was maintained at a high level, compared with the pre-operation level. The patterns of BAP and TRAP activity in the coccyges specimens were similar to those seen in the sera. The expression profiles of TRAP, RANK, and RANKL proteins in the coccyx specimens were similar to the pattern of serum TRAP activity, while the profiles of the BAP and OPG proteins were similar to the pattern of serum BAP activity in OVX rats. The changes in the mRNA expression levels of the osteogenic proteins were similar to those for protein expression. These biochemical changes in OVX rats were confirmed by immunohistochemical studies. Our results suggest that not only osteoclastogenesis accelerated but also osteoblastogenesis transiently increased during the early phase of osteoporosis.