Prediction of oral appliance treatment outcome in obstructive sleep apnoea syndrome: a preliminary study.

OBJECTIVE: Predictors of treatment outcome of oral appliances (OAs) in patients with obstructive sleep apnoea syndrome (OSAS) are not known. There is a pressing need for simple, clinically useful tools to predict treatment outcome. This study aimed to identify predictors of successful OA therapy for OSAS, including evaluation of pharyngeal morphology, which can be measured during routine examination by an otorhinolaryngologist. METHODOLOGY: This was a prospective study of 26 OSAS patients treated with OAs. A favourable outcome was obtained in 14 patients (responders) but not in 12 patients (nonresponders). The baseline patient characteristics and polysomnography and rhinopharyngeal findings were analysed. RESULTS: Body mass index (BMI) was significantly lower in responders versus nonresponders (23.6 ± 2.8 vs. 27.9 ± 4.7 kg/m2; p < 0.05). Pharyngeal morphology, age, sex and nasal resistance did not differ between the groups. Multiple regression analysis showed that BMI was a significant predictor of improvement in the apnoea/hypopnoea index after OA treatment (p < 0.05). CONCLUSION: Here we demonstrated that BMI is a favourable predictor of OA treatment outcome in OSAS patients. Among the OSAS patients, responders had wider retroglossal spaces than nonresponders.

Difference in dental arch size between obese and non-obese patients with obstructive sleep apnoea.

A large tongue is recognised as a factor that increases the collapsibility of the upper airway in obstructive sleep apnoea (OSA) patients. We hypothesised that the propensity to develop severe OSA could be minimised if the dental arches were enlarged in obese OSA people who are thought to have a large tongue. We therefore compared the size of the dental arches in obese and non-obese OSA patients. Using a lateral cephalogram and study models, we compared the sizes of the tongue and dental arches in 23 obese and 23 non-obese Japanese male OSA patients, who were matched for age, apnoea hypopnea index (AHI) and maxillomandibular size. The median age (years) and AHI (events per hour) for the obese and non-obese groups were 36·5 and 39·0, and 13·4 and 14·3, respectively. The maxillomandibular size was matched with regard to SNA, SNB and lower face cage obtained from cephalometric measurements. The parameters that were measured for the study model included dental arch width, dental arch length, overjet and overbite. Tongue size (P < 0·05) and both upper (P < 0·01) and lower (P < 0·05) dental arch widths were significantly larger in obese than in non-obese OSA patients, and there was no difference in the severity of OSA between the two groups. These findings suggest that the tongue was larger and dental arches were enlarged in obese patients compared with non-obese patients under the same disease severity. Wider dental arches in obese OSA patients may help to offset the impact of the enlarged tongue on upper airway patency.

Optimal positive airway pressure predicts oral appliance response to sleep apnoea.

Patients with less severe obstructive sleep apnoea (OSA) are usually prescribed oral appliances and/or smaller optimal nasal continuous positive airway pressure (P(nCPAP)) in nCPAP therapy. We hypothesised that OSA patients with greater P(nCPAP) would not respond favourably to oral appliances. Oral appliances were inserted in nCPAP users after washing-out the nCPAP effect. Follow-up polysomnography was undertaken with the adjusted oral appliance in place. The predictability of P(nCPAP) was evaluated with receiver-operating characteristic (ROC) curves. The median baseline apnoea/hypopnoea index (AHI) was reduced with the oral appliance from 36 to 12 events.h(-1) in 35 patients. When responders were defined as patients showing a follow-up AHI of <5 events.h(-1) with >50% reduction in baseline AHI, the area under the ROC curve for P(nCPAP) was 0.76. The best cut-off value of P(nCPAP) turned out to be 10.5 cmH(2)O with a high negative predictive value (0.93) and a low negative likelihood ratio (0.18). OSA patients with a P(nCPAP) of >10.5 cmH( 2)O are unlikely to respond to oral appliance therapy. This prediction is clinically helpful to both OSA patients and medical personnel in discussing oral appliances as a temporary substitute and/or alternative for nCPAP.

Characterization of rat hepatoma glucosamine 6-phosphate synthase and its relation to liver and fetal forms.

Glucosamine 6-phosphate synthase (EC 5.3.1.19) purified from various rat tissues by a procedure involving chromatography on diethylaminoethyl Sephadex and hydroxylapatite were characterized by means of isoelectric focusing. The non-hepatic isozyme, previously reported to be present in Yoshida sarcoma, has a pI of 4.1 and is distinguished from the hepatic isozyme, with a pI of 5.0. The pI 4.1 form is the major one in all of the fast-growing, transplantable hepatomas studied. Although not detectable in 19-day fetal liver or normal adult liver, the pI 4.1 form has been observed in the whole 12-day fetus and adult brain as almost the sole form of glucosamine 6-phosphate synthase.

Glucosamine 6-phosphate synthase of regenerating rat liver.

When rats were subjected to partial hepatectomy, glucosamine 6-phosphate synthase (EC 5.3.1.19) of the remaining liver underwent alterations both in activity and in molecular form. To study the molecular alterations, glucosamine 6-phosphate synthase was purified from regenerating as well as control liver and was analyzed by isoelectric focusing. Although control liver exhibited only one form of glucosamine 6-phosphate synthase with a pI of 5.0, sequential and transient appearance of three other forms, with pI values of 4.3, 4.8, and 4.5, respectively, was observed for regeneration liver within 72 hr following partial hepatectomy. Laparotomy, on the other hand, induced in the liver only the pI 4.8 form, and injection of a mixture containing triiodothyronine, amino acids, glucagon, and heparin induced only the pI 4.3 and 4.5 forms. It therefore appears that the pI 4.3 and 4.5 forms, but not the pI 4.8 form, are associated with hepatic DNA synthesis. The pI 4.8 form is induced in the liver in response to surgical stress.

Inhibition of cell proliferation by Rana catesbeiana and Rana japonica lectins belonging to the ribonuclease superfamily.

Two frog egg lectins [Rana catesbeiana lectin (SBL-C) and Rana japonica lectin] preferentially agglutinate a large variety of human and animal tumor cells but not blood cells, lymphocytes, or fibroblasts. These lectins belong to the superfamily of pyrimidine base-specific RNases. The two lectins bound to a heparin-Sepharose column and were eluted from the column by an increase of NaCl molarity. Both their tumor cell-agglutinating activity and RNase activity were inhibited by heparin, and also by polyamines, such as spermine. Both lectins inhibited P388 leukemia cell proliferation. The inhibitory activity of SBL-C was blocked by addition of heparin. SBL-C inhibited protein synthesis by P388 cells, but RNase A did not. No lectin-induced antiproliferative effect was observed after sialidase treatment of cells. The antiproliferative activity of SBL-C was also inhibited by ammonium chloride treatment. These results suggest that internalization of the lectins by lectin receptor (sialoglycoconjugate)-mediated endocytosis is followed by cell death due to inhibition of protein synthesis. Administration of SBL-C i.p. delayed time to death in mice receiving i.p. transplants of Sarcoma 180 and Mep II cells.

Metabolism of exogenous N-acetylglucosamine in extracts of rat kidney, liver and hepatoma.

1. The metabolism of exogenous N-acetylglucosamine (GlcNAc) in rat kidney extracts was greatly stimulated by fructose 1,6-diphosphate (Fru-1,6-P2) and to a lesser extent by phosphoenolpyruvate. They served as a generator of ATP. Under these conditions, the majority of metabolized GlcNAc was recovered in the form of glycolytic intermediates. 2. The metabolism of exogenous GlcNAc in rat liver extracts was stimulated by phosphoenolpyruvate but not by Fru-1,6P2. With phosphoenolpyruvate present, most of the metabolized GlcNAc was recovered as sialic acid. 3. The metabolism of exogenous GlcNAc in rat hepatoma (AH-130) extracts was stimulated by Fru-1,6-P2 and to a lesser extent by phosphoenolpyruvate. Even with phosphoenolpyruvate present, the synthesis of sialic acid was extremely small. In these respects, hepatoma extracts resemble kidney extracts rather than those of liver.

Studies on UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase of rat liver and hepatomas.

When homogenates of rat liver and hepatomas were centrifuged at 78 000 X g, over 90% of liver N-acetylglucosaminyltransferase assayed with beta-galactosidase- and beta-N-acetylhexosaminidase-treated asialofetuin as acceptor was recovered in the particulate fraction, while as much as 24% of hepatoma transferase was in the supernatant fraction. The particulate transferase solubilized by 0.2% sodium deoxycholate emerged from a DEAE-cellulose column at 0.04 M NaCl (transferase A). The supernatant fractions from all the hepatomas tested contained a second N-acetylglucosaminyltransferase eluted from the column at 0.02 M NaCl (transferase B). Transferase B was absent from liver supernatant fraction. The activities of these transferases toward various acceptors and the effect of beta-N-acetylhexosaminidase on their products suggest that both transferases are UDP-N-acetylglucosamine : alpha-mannoside beta-N-acetylglucosaminyltransferase. Although ovalbumin and glycopeptide V, which was isolated from pronase digest of ovalbumin, were good acceptors, transferase A utilized ovalbumin and glycopeptide V with apparent Km values of 0.44 and 0.33 mM, respectively, whereas the corresponding values for transferase B were 4.5 and 0.050 mM.

Stabilization of glucosaminephosphate synthase from rat liver by hexose 6-phosphates. Properties and interconversion of two molecular forms.

Glucosaminephosphate synthase (glucosaminephosphate isomerase (glutamine-forming), EC 5.3.1.19) prepared from rat liver by extraction in the presence of glucose 6-phosphate (Glc-6-P) followed by precipitation with (NH4)2SO4 is susceptible to digestion by trypsin. This enzyme, designated form A, can be converted to tryptic-insusceptible form B upon incubation with Glc-6-P or fructose 6-phosphate (Fru-6-P) at 37 degrees C. The two forms also differ in the degree of activation by dithiothreitol, the degree of inhibition by methyl-glyoxal and the behavior on DEAE-Sephadex and Sephadex G-200 column chromatography. During purification with DEAE-Sephadex followed by hydroxyapatite, form B is converted to form A if Fru-6-P is absent and form A to form B if Fru-6-P is present. The two forms are therefore intercovertible. Under the conditions of purification, form B is more stable than form A, since the purity and yield of the final product are greater with form B than with form A. These findings suggest that the two forms of glucosaminephosphate synthase differ conformationally and that the equilibrium position depends on the concentration of Fru-6-P. Glc-6-P is effective only when it gives rise to Fru-6-P by mediation of glucose-phosphate isomerase.

Glucosaminephosphate synthase of human liver.

Although human liver contains glucosaminephosphate synthase (glucosaminephosphate isomerase (glutamine-forming), EC 5.3.1.19), its activity is rapidly lost during the course of extraction. The inactivation, however, is largely prevented if the extraction medium contains isopropanol at 1% concentration; using these "stabilized" extracts, the glucosaminephosphate synthase activity of human liver has been shown to be similar to the activity previously reported in rat liver. The enzyme precipitated from these extracts by (NH4)2SO4 is inhibited by UDP-N-acetylglucosamine, the concentration required to produce a half-maximal inhibition being 6 muM. These results seem to be sufficient to postulate that glucosaminephosphate synthase is important for UDP-N-acetylglucosamine synthesis in human liver. In contrast to the rat liver enzyme, the (NH4)2SO4-precipitated human liver enzyme is resistant to trypsin and undergoes no conversion reaction when incubated with glucose 6-phosphate.

Hypertriacylglycerolemia and adipose tissue lipoprotein lipase activity in the Nagase analbuminemic rat.

In Nagase analbuminemic rats, serum triacylglycerol levels were significantly elevated. This abnormality was accompanied by decreased adipose tissue fat stores, and both were more marked in female than in male rats. Parametrial adipose tissue lipoprotein lipase activity was determined in normally fed female rats. When expressed per mg protein, the activity in analbuminemic rats was only 35% of that in control rats. The activity in analbuminemic rats, however, could be increased as in control rats by refeeding starved animals with a fat-free and carbohydrate-rich diet, and the peak values recorded were the same with the two groups. Treatment of animals with streptozotocin lowered adipose tissue lipoprotein lipase activity in both groups to similar levels. These results suggest that hypertriacylglycerolemia associated with analbuminemia may be caused, at least in part, by altered hormonal control of adipose tissue lipoprotein lipase activity.

Characterization of multiple forms of histone phosphatase in rat liver.

By using chromatography on DEAE-cellulose, aminohexyl-Sepharose 4B and Sephadex G-200, rat liver extract was shown to contain at least three fractions, IA, IB and II, of histone phosphatase. Fractions IA and II are probably the same enzymes as the previously described glycogen synthase phosphatase and phosphorylase phosphatase, respectively, but IB exhibits noticeable activities only with phosphohistone as substrate. Approximate molecular weights of 69 000, 300 000 and 160 000 were determined by gel filtration on Sephadex G-200 for IA, IB and II, respectively.

Molecular cloning of cDNA for the catalytic subunit of rat liver type 2A protein phosphatase, and detection of high levels of expression of the gene in normal and cancer cells.

A cloned cDNA encoding a catalytic subunit of type 2A protein phosphatase from a rat liver cDNA library was obtained by use of a synthetic oligonucleotide corresponding to the tryptic peptide sequence of the purified enzyme. There was only a single amino acid difference between the deduced amino acid sequence of the clone obtained and those of the catalytic subunits, 2A alpha, of the rabbit skeletal muscle, porcine kidney and human liver enzymes, suggesting that this clone was a rat 2A alpha cDNA. On Northern blot analysis using a cDNA fragment as a probe, three mRNA species were detected in rat liver: a major mRNA of 2.0 kb and a minor one of 2.7 kb under high stringency conditions, and also a 1.1 kb mRNA under low stringency conditions. The 2A alpha gene was found to be highly expressed in various tissues of rat, especially the brain. High levels of expression of the gene were also detected in mouse NIH3T3 cells and their transformants, and in human cancer cell lines as well as a human immortalized cell line.

Activation of a D-form of rabbit muscle glycogen synthase by Ca2+-activated protease.

Glycogen synthase isolated from rabbit skeletal muscle as a D-form (synthase D2) is activated by a rat liver cytosolic protein differing from any of the known protein phosphatases (D2 activase). Although reversible by phosphorylation by cyclic AMP-dependent protein kinase, the activation is a result of limited proteolysis by D2 activase, which has been identified as the Ca2+-activated protease.

Evidence for sialidase hydrolyzing gangliosides GM2 and GM1 in rat liver plasma membrane.

Rat liver plasma membrane removed sialic acid from mixed bovine brain gangliosides more efficiently than from sialyllactose and orosomucoid with an optimal pH of 4.5. When individual gangliosides, each labeled with [14C]sialic acid or [3H]sphingosine, were tested, not only GD1a and GM3 but also GM2 and GM1, both of which had been considered to resist mammalian sialidases, were desialylated. The products of GM2 and GM1 hydrolysis were identified as asialo-GM2 and asialo-GM1, respectively, by thin-layer chromatography.

Effects of a titratable oral appliance on supine airway size in awake non-apneic individuals.

STUDY OBJECTIVES: To define morphological changes in the upper airway and its surrounding structures after the insertion of a titratable mandibular repositioner. DESIGN: Ten non-apneic adult males participated in this study. A set of supine lateral cephalograms was taken for each subject at the end of expiration with a titratable oral appliance in place in four mandibular positions: most retruded (RP), maximum protrusion (MAX), 33% of MAX (MAX33), and 67% of MAX (MAX67). Changes in the anteroposterior width of the upper airway, positions of the hyoid bone and the third cervical vertebra were compared between the four mandibular positions. An ANOVA was used to test for statistical significance. SETTING: N/A. PATIENTS OR PARTICIPANTS: N/A. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: The anteroposterior width of the velopharynx significantly increased when the mandible was advanced from RP to MAX67 and MAX. However, there were no significant changes in the anteroposterior width of the oropharynx. Significant forward displacement of the hyoid bone and third cervical vertebra together with the mandible was found in MAX67 and MAX compared to RP. CONCLUSION: Especially in MAX67 and MAX, the titratable oral appliance significantly enlarges upper airway size in the velopharynx and results in a forward displacement of the hyoid bone and the third cervical vertebra.

Catalytic lectin (leczyme) from bullfrog (Rana catesbeiana) eggs.

Catalytic lectins (leczymes) of frog eggs are sialic acid-binding lectins that have intrinsic RNase activity. They inhibit tumor cell proliferation in vitro and in vivo, although their cytotoxic mechanism remains unclear. RNase A has no tumoricidal activity. It is hypothesized that leczymes bind to cell surface sialoglycoconjugate receptors, enter the cell, and subsequently degrade RNA. In order to investigate the cytotoxic mechanism of cSBL, a leczyme from Rana catesbeiana eggs, we established cSBL-resistant clone RC-150 from mouse leukemia P388 cells. cSBL-treated P388 cells showed extensive RNA degradation over the course of 1 h, whereas cSBL-treated RC-150 cells showed no RNA degradation even over the course of 24 h. Treatment of P388 cells with cSBL led to decreased concentration of intracellular Ca2+, decreased protein kinase A activity, and increased protein kinase G activity. Incubation with cSBL decreased glutathione levels and enhanced glutathione-S-transferase (GST) activity in P388 cells, but had no effect on RC-150 cells. We conclude that cSBL-specific degradation of RNA occurs in cSBL-sensitive tumor cells, that cSBL leads to alteration of signal transduction and an intracellular protein kinase cascade reaction, and that internalized cSBL is detoxified by GST or thioltransferase. Our findings support a bifunctional model in which a leczyme is both an adhesive protein (binding to sialoglycoconjugates) and an enzyme (displaying RNnase activity).

Characterization of the major sialidases of various types of rat blood cells: their comparison with rat liver sialidases.

The substrate specificity and subcellular location of the major sialidases of three types of rat blood cells were characterized and compared with those of the known three types of rat liver sialidase, which have been designated intralysosomal, cytosolic, and plasma membrane-associated sialidases. Platelets and leucocytes contain mainly an acid sialidase, which is highly active towards oligosaccharides and 4MU-NeuAc, and erythrocytes possess a high level of a sialidase acting on gangliosides. A Percoll gradient centrifugation study showed that the former is located in lysosomes and the latter in plasma membrane. When the sialidase was solubilized and partially purified from erythrocyte ghosts, the enzyme was found to hydrolyze actively gangliosides but only poorly other substrates such as 4MU-NeuAc, oligosaccharides, and glycoproteins. The sialidase partially purified from rat liver membrane fraction exhibited the same substrate specificity. It is concluded that the major sialidase of platelets and leucocytes corresponds to hepatic intralysosomal sialidase while erythrocytes contain almost exclusively a ganglioside sialidase which corresponds to hepatic plasma membrane sialidase.

Identification of a rat liver protein-tyrosine phosphatase similar to human placental PTPase-1B using quantitatively phosphorylated protein substrates.

Erythrocyte Band 3 protein (Band 3), brain microtubule associated protein 2 (MAP2), and tubulin were phosphorylated to high stoichiometries (1-6 mol Pi/mol protein) on tyrosine residues using a rat spleen protein-tyrosine kinase in the presence of polylysine. After total removal of polylysine, the quantitatively phosphorylated proteins as well as tyrosine-glutamate copolymer [Poly(Glu4, Tyr1)], which was also phosphorylated (1.5 mol/mol) by the kinase, were employed to assay rat liver protein-tyrosine phosphatases (PTPases). Of the four partially purified PTPases termed L1, L2, L3, and L4, PTPase L1 was previously purified to homogeneity and demonstrated to be a novel enzyme with sequence similarity to src-homology region 2 [Hiraga, A. et al. (1992) Eur. J. Biochem. 209, 195-206]. In the present work PTPase L2 was purified to near homogeneity by a procedure involving chromatography on DEAE-cellulose, Blue Sepharose CL-6B, hydroxylapatite, Phenyl Sepharose CL-4B, and TSKgel Heparin-5PW. PTPase L2 was purified 20,000-fold with a recovery of 0.9% from the extract and 0.005 mg was isolated from 300 g of liver. The highly purified PTPase L2 showed a major protein band of 36 kDa on SDS/polyacrylamide gel electrophoresis. PTPase L2 had a specific activity of about 6,000 nmol of P1 released min-1.mg-1 toward either Band 3 or poly(Glu4, Tyr1), the values being within the range of those obtained for PTPases purified thus far. PTPase L2 dephosphorylated Band-3 9-fold and 5-fold faster than tubulin and MAP2, respectively, under the assay conditions employed.(ABSTRACT TRUNCATED AT 250 WORDS)