Comparative analysis of different enzyme immunoassays for assessment of phosphatidylserine-dependent antiprothrombin antibodies

Phosphatidylserine-dependent antiprothrombin antibodies (aPS/PT) were strongly correlated with the presence of lupus anticoagulant showing a high specificity for the diagnosis of antiphospholipid syndrome. However, the main criticism for the clinical applicability of aPS/PT testing is the lack of reproducibility of the results among laboratories. In this study, we measured IgG and IgM aPS/PT using our original in-house enzyme-linked immunosorbent assays (ELISA) and commercial ELISA kits to assess the assay performance and to evaluate the accuracy of aPS/PT results. The study included 111 plasma samples collected from patients and stored at our laboratory for aPS/PT assessment. Sixty-one samples were tested for IgG aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite? aPS/PT IgG ELISA kit (INOVA Diagnostics, Inc., USA). Fifty samples were evaluated for IgM aPS/PT using two assays: (1) aPS/PT in-house ELISA and (2) QUANTA Lite? aPS/PT IgM ELISA kit (INOVA Diagnostics). Ninety-eight percent of samples yielded concordant results for IgG aPS/PT and 82 % for IgM aPS/PT. There was an excellent agreement between the IgG aPS/PT assays (Cohen κ = 0.962) and moderate agreement between the IgM aPS/PT assays (κ = 0.597). Statistically significant correlations in the aPS/PT results were obtained from both IgG and IgM aPS/PT assays (r = 0.749, r = 0.622, p < 0.001, respectively). In conclusion, IgG and IgM detection by ELISA is accurate. The performance of aPS/PT is reliable, and concordant results can be obtained using different ELISA methods.     

IN VIVO TRAFFICKING OF LONG-CIRCULATING LIPOSOMES IN TUMOUR-BEARING MICE DETERMINED BY POSITRON EMISSION TOMOGRAPHY

Various kinds of long-circulating liposome, such as ganglioside GM1-, polyethyleneglycol- (PEG-), and glucuronide-modified liposomes, have been developed for passive targeting of liposomal drugs to tumours. To evaluate the in vivo behaviour of such long-circulating liposomes, we investigated the liposomal trafficking, especially early trafficking just after injection of liposomes, by a non-invasive method using positron emission tomography (PET). Liposomes composed of dipalmitoylphosphatidylcholine, cholesterol, and modifier, namely, GM1, distearoylphosphatidylethanolamine (DSPE)–PEG or palmityl-D -glucuronide (PGlcUA), were labelled with [2-¹⁸F]-2-fluoro-2-deoxy-D -glucose ([2-¹⁸F]FDG), and administered to mice bearing Meth A sarcoma after having been sized to 100 nm. A PET scan was started immediately after injection of liposomes and continued for 120 min. PET images and time–activity curves indicated that PEG liposomes and PGlcUA liposomes were efficiently accumulated in tumour tissues time dependently from immediately after injection. In contrast, GM1 liposomes accumulated less in the tumour as was also the case for control liposomes that contained dipalmitoylphosphatidylglycerol (DPPG) instead of a modifier. Long-circulating liposomes including GM1 liposomes, however, remained in the blood circulation and avoided liver trapping compared with control DPPG liposomes. These data suggest that PGlcUA and PEG liposomes start to accumulate in the tumour just after injection, whereas GM1 liposomes may accumulate in the tumour after a longer period of circulation.     

Inhibitory Effects of Partially Decomposed Alginate on Production of Glucan and Organic Acid by Streptococcus sobrinus 6715

Our previous study has already clarified that partially decomposed alginate (Alg53) by Vibrio alginolyticus SUN53 has a competitive inhibitory effect on sucrase. The objective of this study is to evaluate the influence of Alg53 on the production of glucan from sucrose by glucosyltransferase and acid from glucose by Streptococcus sobrinus 6715. Glucosyltransferase was prepared from cultural medium of S. sobrinus using ultrafiltration and hydroxyapatite chromatography. In order to examine the inhibitory effect of Alg53 for production of glucan by GTase, partially purified GTase, sucrose and Alg53 solution were incubated at 37°C. The influence of Alg53 on the production of acid from glucose was evaluated by a degree of pH decline during the incubation for 60 min. The original Alg53 solution markedly inhibited to 21% of the synthesis of water-insoluble glucan from sucrose and that of 10-fold diluted of Alg53 solution was 23%. However, the production of water-soluble glucan from sucrose by GTase was hardly affected by Alg53. Furthermore, Alg53 suppressed dose-dependently pH decline by organic acid converted from glucose. These results suggest that Alg53 is expected as a functional food material which prevents or reduces dental caries.     

Plasma endothelin-1 levels depress optic nerve head circulation detected during the glucose tolerance test

Purpose To determine the relationship between the changes in optic nerve head (ONH) circulation and the level of plasma endothelin-1 (ET-1) during the glucose tolerance test (GTT). Methods Twenty-six healthy volunteers with normal GTT and 15 patients with mild hyperglycemia and abnormal GTT were studied. The ONH circulation [square blur rate (SBR) value], blood pressure, intraocular pressure (IOP), blood glucose, blood insulin and plasma ET-1 were determined before and every hour up to 3 h after an oral intake of 75 g of glucose. Results The SBR increased in the normal glucose tolerance group at all times during the GTT, but it decreased significantly in the abnormal glucose tolerance group (P < 0.05). Before the GTT, the plasma ET-1 level was not significantly different in the two groups; however, the level increased 1 h after the oral GTT in the abnormal glucose tolerance group (P < 0.05). No significant changes were observed in mean blood pressure or IOP. Conclusions ONH circulation increased after glucose intake in the normal glucose tolerance group and remained high even after the blood glucose level had returned to its baseline. The decrease in ONH circulation in the abnormal glucose tolerance group was attributed partly to the increased ET-1.     

Localization and function of the brainstem neuronal mechanism for respiratory control]

Recently, the neural mechanism of respiratory control in the brainstem has been extensively analyzed mainly in vitro. A neuronal group in the ventrolateral medulla, the ventral respiratory group (VRG), is important in respiratory rhythm and pattern generation. A small region in the rostral VRG, the pre-B?tzinger Complex (pre-B?tC), is the kernel of respiratory rhythmogenesis. A novel region ventrolateral to the facial nucleus, the para-facial respiratory group (pFRG), was found and has been considered to also generate respiratory rhythm. These two oscillators, pre-B?tC and pFRG, are coupled and synchronized. In central chemoreception, small cells surrounding fine vessels in the most superficial layer in the rostral ventral medulla are considered to be primary chemoreceptor cells. Currently, several kinds of neurotransmitters, including glutamic acid, serotonin, ATP and acetylcholine, are considered to play important roles in the signal transduction from chemoreceptor cells to the VRG and other parts of the respiratory neuronal network. The mechanism of respiratory suppression by opioids is the blockade of excitatory drive to the pre-B?tC. Although recently we have elucidated that propofol, widely used intravenous anesthetics, suppresses respiratory output through the activation of GABAA receptor, the mechanism of respiratory depression by inhalation anesthetics remains unknown.     

Beneficial effect of T-1095, a selective inhibitor of renal Na+-glucose cotransporters,on metabolic index and insulin secretion in spontaneously diabetic GK rats

1. To investigate the pharmacological effects of T-1095, this novel derivative of phlorizin was administered to GK rats for 8 weeks. T-1095 treatment significantly lowered plasma glucose and glycosylated haemoglobin (HbA1c) levels, but did not significantly affect bodyweight. 2. T-1095 treatment did not affect 3.3 mmol/L glucose-induced insulin secretion in the isolated perfused pancreas of GK rats. 3. The peak insulin release in T-1095-treated GK rats was significantly higher during the first phase than in untreated GK rats (3-4 min after beginning 16.7 mmol/L glucose perfusion). The total amount of insulin secreted during the first phase in T-1095-treated GK rats was significantly higher than in untreated GK rats (35.3 +/- 1.4 vs. 27.3 +/- 2.5 ng in T-1095-treated compared with untreated rats, respectively). 4. During the second phase, insulin release in T-1095-treated GK rats was somewhat higher than in untreated GK rats (7-30 min after beginning 16.7 mmol/L glucose perfusion). The total amount of insulin secreted during the second phase in T-1095-treated GK rats was significantly higher than in untreated GK rats (88.2 +/- 6.1 vs. 68.1 +/- 5.7 ng, respectively). 5. The total amount of insulin secreted during perfusion in T-1095-treated GK rats was significantly higher than in untreated GK rats (123.5 +/- 7.3 vs. 95.4 +/- 7.7 ng, respectively). 6. These data show that the metabolic indices, plasma glucose and HbA1c levels and insulin secretion are significantly improved by T-1095 treatment in GK rats, which are spontaneously diabetic rats, suggesting its usefulness as a novel oral therapeutic antidiabetic agent.