Overexpression of suppressor of cytokine signalling-5 augments eosinophilic airway inflammation in mice

BACKGROUND

Enhanced expression of the suppressor of cytokine signalling (SOCS)-5 might be of therapeutic benefit for T-helper type 2 (Th2) dominant diseases, as its expression is reported to result in a reduction of Th2 differentiation in vitro due to the inhibition of IL-4 signalling.

OBJECTIVE

To investigate the regulatory role of SOCS-5 in vivo, we explored the phenotype of an experimental asthma model developed in SOCS-5 transgenic (Tg) mice.

METHODS

The SOCS-5 Tg mice or wild-type (WT) mice were sensitized and repeatedly challenged with ovalbumin (OVA). We examined bronchoalveolar lavage fluid (BALF), lung specimens, and airway hyperresponsiveness (AHR) to methacholine.

RESULTS

The production of IFN-gamma by CD4(+) T cells from unprimed SOCS-5 Tg mice was significantly increased in comparison with unprimed wild-type mice, indicating that SOCS-5 Tg mice have a Th1-polarizing condition under natural conditions. However, in an asthma model, significantly more eosinophils in the airways and higher levels of IL-5 and IL-13 in BALF were observed in the SOCS-5 Tg than the wild-type mice. AHR in the asthma model of SOCS-5 Tg was also more enhanced than that of wild-type mice. OVA-stimulated CD4(+) T cells from the primed SOCS-5 Tg mice produced significantly more IL-5 and IL-13 than CD4(+) T cells from wild-type mice.

CONCLUSION

Our results demonstrate that the overexpression of SOCS-5 does not inhibit Th2 response, but rather augments the phenotype of the asthma model in vivo. This finding throws into question the therapeutic utility of using enhancement of SOCS-5 expression for Th2-dominant disease.

Beneficial effect of interferon-β treatment in patients with multiple sclerosis is associated with transient increase in serum IL-6 level in response to interferon-β injection

In order to predict the clinical benefit of interferon-beta (IFN-beta) to patients with multiple sclerosis (MS), the following markers were investigated; (1) chronological change of cytokines (IFN-gamma, TNF-alpha, IL-6, IL-10, and TGF-beta) after administration of IFN-beta, (2) untoward effects of IFN-beta such as headache and arthralgia, (3) backgrounds of the patients such as age and relapse rate, (4) efficacy of IFN-beta therapy assessed by the change of relapse rate and progression of disability. Chronological blood sampling was performed 0, 10, and 24 h after injection of IFN-beta. The increase of serum IL-6 level in response to IFN-beta administration was associated with headache, arthralgia, relapse rate before treatment, and disability score at the initiation of the therapy. Significant association of change of serum TNF-alpha with age and headache was also observed. The important finding in this study was that patients with a transient increase in IL-6 in response to IFN-beta showed a slow disease progression. This result suggests that this transient increase in the serum IL-6 predicts favorable response to IFN-beta treatment.

A comparison of two citrate anticoagulation regimens for continuous veno-venous hemofiltration

AIMS

To assess the safety and efficacy of two different commercial citrate containing pre-filter replacement fluids during continuous veno-venous hemofiltration (CVVH) in patients with frequent filter clotting.

SETTING

Four intensive care units.

PATIENTS

Sixty-three critically ill patients with acute renal failure (ARF).

DESIGN

Prospective observational study.

METHODS

We used a commercial citrate fluid (citrate: 11 mmol/L -fluid A) as predilution replacement for CVVH. We then changed to a new commercial citrate fluid (citrate: 14 mmol/L-fluid B) as replacement fluid and performed statistical comparisons. Replacement fluid rate was fixed at 2,000 ml/hour.

RESULTS

Filter life was 12.2 hour with fluid A compared with 17.1 hour with fluid B on average (p=0.0001). Mean post filter ionized calcium concentration was 0.52 mmol/L with fluid A compared with 0.40 mmol/L with fluid B (p<0.0001). Citrate intolerance led to cessation of treatment in one patient with fluid A and one patient with fluid B. Overall ionized calcium levels were higher (A: 1.18 vs B: 1.13 mmol/L; p<0.0001) and bicarbonate was lower (A: 22.4 vs B: 24.5 mmol/L; p<0.0001) during treatment with fluid A. Alkalemia was seen in 10 patients treated with fluid A and 16 patients treated with fluid B (NS).

CONCLUSIONS

We have developed a simple approach to regional citrate anticoagulation for CVVH using a commercial citrate-containing fluid as replacement fluid. Increasing citrate concentration from 11 to 14 mmol/L increased filter life while maintaining relative safety and simplicity.

Risk factors for dysbaric osteonecrosis

OBJECTIVES

Dysbaric osteonecrosis (DON) is a complication of ineffective decompression following exposure to high-pressure environments. This study was designed to determine risk factors for the occurrence of DON in divers.

METHODS

Fifty-six male divers received skeletal examinations by radiography to assess the occurrence of DON. A questionnaire was used to obtain clinical and diving information, including diving experience and maximum diving depth. Blood samples were collected to analyse the levels of plasminogen activator inhibitor (PAI)-1, cholesterol, triglyceride, low-density lipoprotein, very low-density lipoprotein, high-density lipoprotein, apolipoprotein A1 and apolipoprotein B.

RESULTS

Lesions of DON were detected in 31 of the 56 (55%) divers. Multivariate logistic regression analysis showed that high levels of PAI-1, a coagulation marker (odds ratio 4.281; P=0.0296) and great maximum diving depth (odds ratio 5.627; P=0.0231) were independent predictors of DON.

CONCLUSIONS

This study has shown the presence of coagulation abnormality in divers with DON. This result suggests that a pharmacological approach incorporating the use of an anticoagulant may represent a potential strategy for the prevention of DON.

A pilot study of pulse contour cardiac output monitoring in patients with septic shock

OBJECTIVE

To assess the relationship between PiCCO-derived signals and conventional measures of pre-load and gas exchange in patients with septic shock.

METHODS

Prospective observational study of 23 patients with septic shock. Scheduled collection of clinical, conventional haemodynamic and PiCCO derived variables. Statistical analysis of correlations.

RESULTS

Patients had a mean SAPS II score of 53.5 +/- 14.5 with 78.3% on mechanical ventilation at PiCCO insertion. PiCCO monitoring lasted a mean of 4.3 +/- 2.9 days. SAPS II predicted 28-day mortality was 54.2%, while actual mortality was 39.1%. At PiCCO insertion, there was an inverse correlation between cardiac (CI) and extravascular lung water index (EVLWI) (r = -0.442; p < 0.05). During treatment, the most significant correlation was between the PiCCO-derived global end-diastolic volume index (GEDVI) and PaO(2)/F(I)O(2) ratio (r = 0.386; p < 0.01). There was also a correlation between changes in GEDVI and changes in CI (r = 0.329; p < 0.01). Increases in EVLWI correlated with decreases in PaO(2)/F(I)O(2) ratio( )(r = -0.332; p < 0.01).

CONCLUSIONS

PiCCO-derived pre-load and extravascular lung water signals show logical associations with conventional indirect indicators of haemodynamic and fluid status suggesting physiological and clinical relevance.

Kidney failure associated with liver transplantation or liver failure: the impact of continuous veno-venous hemofiltration

BACKGROUND AND AIMS

The short-term outcome of critically ill patients with kidney failure combined with severe liver failure or orthotopic liver transplantation (OLTx) is poor. We sought to test the hypothesis that, with the exclusive use of continuous veno-venous hemofilration (CVVH) with minimal heparin-anticoagulation, the short and long-term outcomes of these patients would be improved.

PATIENTS

Sixty-six consecutive patients with combined liver and kidney failure

SETTING

Intensive Care Unit of tertiary hospital

DESIGN

Retrospective interrogation of prospectively collected databases

INTERVENTION

Treatment of all patients with continuous veno-venous hemofiltration (CVVH) by protocol with 2L/h of ultrafiltration rate and minimal use of circuit heparinization. Retrieval of specific information on demographic, clinical, therapeutic and outcome details.

MEASUREMENTS AND MAIN RESULTS

From July 1995 to April 2004, 66 patients with combined liver and renal failure received continuous veno-venous hemofiltration (CVVH). Of these, 26 received liver transplantation and 40 did not. There were no significant differences in age, APACHE II score, bilirubin, ALT, INR or albumin on admission. The average duration of CVVH was 9.5 days for OLTx patients and 5 days for non-transplanted patients (p=0.013). Heparin anticoagulation was used in only 12% of OLTx patients and 20% of non-transplanted patients. ICU mortality was 15% in OLTx patients and 63% in non-transplanted patients (p<0.0005); hospital mortality was 23% compared to 70% (p<0. 001). Mean survival time at follow up was 1,120 days compared to 358 days (p<0.0001).

CONCLUSIONS

ARF associated with OLTx has a much better outcome than ARF without OLTx. Furthermore, management based on a conservative anticoagulation policy and CVVH as the exclusive form of renal support was associated with the best ICU, hospital and long term survival reported so far.

Enhanced expression of suppressor of cytokine signalling-1 in the liver of chronic hepatitis C: possible involvement in resistance to interferon therapy

Interferon-alpha (IFN-alpha) is widely used in the treatment of chronic hepatitis C (CHC). The suppressor of cytokine signalling (SOCS) family has been implicated in the regulation of JAK-STAT signalling, including IFN signalling. The negative effect of SOCS expression on the response of CHC to IFN-alpha is demonstrated here. The transcriptional levels of SOCS-1 and -3 in the livers of 21 patients with CHC and eight controls were investigated by quantitative reverse transcription-polymerase chain reaction. We established stable transfectants of SOCS-1 in a human hepatoma cell line, PLC/PRF/5 and analysed the effects of SOCS-1 on the phosphorylation of IFN-alpha-induced STAT-1 tyrosine by immunoblotting and the expression of antiviral genes by Northern blot. A prospective cohort study on SOCS-1 expression and clinical outcome was carried out in 77 patients with CHC who received IFN therapy. SOCS-1, but not SOCS-3, transcripts in the livers of CHC were significantly higher than controls (P < 0.005). IFN-alpha-induced STAT-1 phosphorylation and the expression of antiviral genes were inhibited in SOCS-1-transfected cells. Patients showing high SOCS-1 expression in the liver had a significantly lower rate of sustained virological response (SVR) to IFN therapy than those with low SOCS-1 expression (P = 0.0014). A multivariate analysis performed with host factors revealed that SOCS-1 staining in the liver can serve as a significant predictor for IFN SVR (P = 0.004). SOCS-1 expression is enhanced in the livers of CHC patients and might be involved in resistance to IFN therapy.

Negligent homicide by traumatic asphyxia

We presented an unusual case of negligent homicide by thorax compression, which is the expanded concept of traumatic asphyxia. A 58-year-old man was restrained in the prone position by six prison officers. They were ordered by their superiors to continue restraining him for about 15 min and the victim died. At the forensic autopsy, typical findings of thorax compression with intramuscular hemorrhages on the back and multiple fractures of the ribs were observed. No evidence of neck compression/smothering or other fatal issues likely to occur by chest compression was found. The reconstruction of the scene corresponded exactly with the localization of the injuries found in the victim. This is the first case of death by pure thorax compression without other fatal factors during intentional restraint, in which the force causing the chest compression was distinctly determined by the autopsy and reconstruction.

Circulating KL-6 levels in patients with drug induced pneumonitis

BACKGROUND

The circulating level of KL-6/MUC1 is a sensitive marker for various interstitial lung diseases. Previous case reports have suggested that KL-6 may also be increased in some patients with drug induced pneumonitis. A study was undertaken to determine whether serum KL-6 could be a marker for particular types of drug induced pneumonitis.

METHODS

The findings of high resolution computed tomographic (HRCT) chest scans of 30 patients with drug induced pneumonitis were reviewed separately by two independent observers. The pneumonitis was classified into four predominant patterns: widespread bilateral consolidation (diffuse alveolar damage, DAD; n=7), fibrosis with or without consolidation (chronic interstitial pneumonia, CIP; n=11), consolidation without fibrosis (bronchiolitis obliterans organising pneumonia or eosinophilic pneumonia, BOOP/EP; n=8), and diffuse ground glass opacities without fibrosis (hypersensitivity pneumonitis, HP; n=4). Serum KL-6 levels were measured by a sandwich enzyme linked immunosorbent assay.

RESULTS

The overall sensitivity of serum KL-6 in detecting drug induced lung disease was 53.3%, which was lower than its sensitivity in detecting other interstitial lung diseases. However, the KL-6 level was increased in most patients with a DAD or CIP pattern (16/18; 88.9%) and was closely correlated with their clinical course. In contrast, serum KL-6 levels were within the normal range in all patients with a BOOP/EP or HP pattern.

CONCLUSIONS

Particular patterns detected by HRCT scanning, such as DAD and CIP but not the BOOP/EP or HP patterns, are associated with increased circulating KL-6 levels in drug induced pneumonitis. Serum KL-6 levels may reflect the clinical activity of the particular disorders.

Postoperative evaluation of pylorus-preserving procedures compared with conventional distal gastrectomy for early gastric cancer

We evaluated postoperative function in 98 patients who underwent surgery for early gastric cancer between 1995 and 1998 to compare the results of pylorus-preserving procedures to those of conventional distal gastrectomy with Billroth I (B-I). The pylorus-preserving procedures included endoscopic mucosal resection (EMR), performed in 12 patients; local resection (Local), performed in 14 patients; segmental resection (Seg), performed in 8 patients; and pylorus-preserving gastrectomy (PPG), performed in 19 patients. B-I was performed in 45 patients. The nutritional status and serum albumin (Alb) levels after PPG, the hemoglobin (Hb) levels after EMR, Local, and PPG, and the present/preoperative body weight ratios after EMR, Local, Seg, and PPG were superior to those after B-I. The time before oral intake was recommenced after EMR and Local, the volume of oral intake tolerated after EMR, Local, Seg, and PPG, and the postoperative hospital stay after EMR were all superior to those after B-I. Moreover, significantly fewer patients suffered reflux symptoms after EMR, Local, and PPG, abdominal fullness after EMR, and early dumping syndrome after EMR, Local, and PPG than after B-I. There was also less evidence of gastritis after EMR, Local, and PPG, and of bile reflux after EMR, Local, and PPG, than after B-I. These findings indicate that pylorus-preserving procedures may result in a better postoperative quality of life for selected patients with early gastric cancer.

Enantiodivergent synthesis of either enantiomer of ABCDE-ring analogue of antitumor antibiotic fredericamycin A via intramolecular [4 + 2] cycloaddition approach

[reaction: see text] An intramolecular enantiodivergent synthesis of both enantiomers of the ABCDE-ring analogue 22 of fredericamycin A is reported. Key steps involve an intramolecular [4 + 2] cycloaddition of 17 and an aromatic Pummerer-type reaction of 19. A lipase-catalyzed enantioselective desymmetrization of prochiral diol 2 using 1-ethoxyvinyl 2-furoate 3 led to the pivotal intermediate (R)-4.

Immunohistochemical analysis of E-cadherin, alpha-catenin, beta-catenin, gamma-catenin, and neural cell adhesion molecule (NCAM) in chordoma

AIMS

The epithelioid features seen in chordoma are unique among mesenchymal tumours. However, no detailed analysis regarding cell-cell communication has been conducted in this epithelioid tumour. The aims of this study were to investigate cell-cell communication in chordoma.

METHODS

By means of immunohistochemical techniques that incorporated a panel of monoclonal antibodies against cell adhesion molecules (CAMs), including E-cadherin, alpha-catenin, beta-catenin, gamma-catenin, and neural cell adhesion molecule (NCAM), the expression of CAMs was studied in 15 specimens of chordoma and eight specimens of chondrosarcoma.

RESULTS

Most chordoma specimens showed some positive immunoreactivity for all the CAMs examined. For the various CAMs investigated, between two and five cases showed diffuse immunoreactions, indicating well preserved expression. Well preserved expression of all the CAMs examined was limited to only one case, thus indicating that the expression of CAMs was decreased in most of the chordoma specimens; however, no significant correlation was found between the decreased expression of CAMs and the histological grade of malignancy, cellular growth pattern, or clinical parameters in chordoma. In chondrosarcoma, only a few specimens showed positive immunoreactivity for CAMs and the expression of E-cadherin, beta-catenin, gamma-catenin, and NCAM was seen more frequently in the chordoma specimens than in the chondrosarcoma specimens.

CONCLUSIONS

These results suggest that the expression of CAMs is associated with the formation and maintenance of chordoma tissue architecture, just as it is in other epithelial tumours or normal tissue. Immunohistochemistry for CAMs was found to be of diagnostic value for discriminating chordoma from chondrosarcoma, and these markers could be used along with the cytokeratins, which are already used for this purpose.

Suppressive effects of genistein dosage and resistance exercise on bone loss in ovariectomized rats

This study was designed to determine whether combined treatments with genistein dosage and moderate resistance exercise would exhibit synergistically preventive effects on bone loss following the onset of menopause. Forty-one 12 wk-old female SD rats were assigned to five groups: 1) Sham operated (Sham); 2) ovariectomized (OVX-Cont); 3) OVX received genistein (OVX-GEN); 4) OVX exercised (OVX-EXE); and 5) OVX treated with both genistein and exercise (OVX-GEN-EXE). All rats were fed a low Ca (0.1%) diet ad libitum. Daily genistein dosage was 12 mg/kg body weight. Exercising rats took 40 sets of 1-min run interspersed with 1-min rest with a 100 g weight on the back on an uphill treadmill at 20 m/min. The experimental duration consisted of the adaptation and treatment periods of 4 weeks each. Uterine weight in OVX-Cont, OVX-GEN, OVX-EXE and OVX-GEN-EXE decreased to about 15% of that in Sham (p < 0.001). The femoral BMD (mg/cm2; mean +/- SE), assessed by DEXA (Lunar), of OVX-Cont was significantly lowered to 206 +/- 5 by -9%, as compared to 226 +/- 2 of Sham (p < 0.001). The BMD of OVX-GEN, OVX-EXE and OVX-GEN-EXE were 217 +/- 2, 217 +/- 2 and 222 +/- 2, respectively, and genistein dosage and resistance exercise equally increased the BMD of OVX rats by 5% (p < 0.01). Combined treatment of genistein and exercise more successfully recovered their decreased BMD by 8% (p < 0.001). BMD of the fourth lumbar vertebrae in OVX-Cont was declined to 191 +/- 7 by -15%, as compared to 225 +/- 4 in Sham (p < 0.001). OVX-EXE and OVX-GEN-EXE gained the BMD by 6% to 205 +/- 4 and 203 +/- 3, respectively, as compared to that of OVX-Cont (p < 0.01). These results suggest the possibility that the combined treatment of genistein dosage and resistance exercise have more beneficial effects by acting rather independently than their separate trials on the prevention of ovx-induced bone loss in femurs.

Gastrointestinal stromal tumor of the stomach: report of a case

We report herein the case of a 70-year-old woman found to have a gastrointestinal stromal tumor (GIST) of the stomach. Preoperative X-ray and endoscopic examination revealed a hemispheric submucosal tumor with central depression in the anterior wall of the gastric fornix. The tumor, which was 3 cm in diameter, was resected by a laparoscopy-assisted procedure. Histologic examination revealed that it was composed of spindle-shaped cells with elongated nuclei, and few mitoses. Most of the tumor cells showed immunoreactivity for vimentin and CD34, but not for alpha-smooth muscle actin, desmin, or S-100 protein. The PCNA index was 40.5%. Thus, the GIST did not show differentiation toward smooth muscle or neural cells. A gastrectomy was not performed because the small size of the tumor, and the paucity of the mitoses indicated that it was benign. Nevertheless, careful and long-term follow-up is needed to monitor for signs of possible local recurrence or distant metastases.

Potent dibasic GPIIb/IIIa antagonists with reduced prolongation of bleeding time: synthesis and pharmacological evaluation of 2-oxopiperazine derivatives

A series of 2-oxopiperazine derivatives, possessing basic moieties at the 3- and the 4-positions, were synthesized and evaluated for their abilities to inhibit platelet aggregation and for their effects on bleeding time. Among the compounds, 2-[(3S)-4-[2-[(4-guanidinobenzoyl)amino]acetyl]-3-[3-[(4-guanidinobenzoyl)amino]propyl]-2-oxopiperazinyl]acetic acid (12c) showed a potent inhibitory effect on platelet aggregation and good dissociation between the efficacy and the bleeding side effect. Intravenous infusion of compound 12c at 1.6 microg/mL/min completely prevented arterial thrombus formation induced by endothelial injury in guinea pigs. The dose of 12c that prolonged the bleeding time to three times the control value was 5.8 microg/mL/min. These results suggest that compound 12c might be useful in the clinical treatment of thrombotic diseases, and we selected 12c (TAK-024) as a candidate for the clinical trials.

SOCS-1/SSI-1-deficient NKT cells participate in severe hepatitis through dysregulated cross-talk inhibition of IFN-gamma and IL-4 signaling in vivo

Suppressor of cytokine signaling-1 (SOCS-1), also known as STAT-induced STAT inhibitor-1 (SSI-1), is a negative feedback molecule for cytokine signaling, and its in vivo deletion induces fulminant hepatitis. However, elimination of the STAT1 or STAT6 gene or deletion of NKT cells substantially prevented severe hepatitis in SOCS-1-deficient mice, while administration of IFN-gamma and IL-4 accelerated its development. SOCS-1 deficiency not only sustained IFN-gamma/IL-4 signaling but also eliminated the cross-inhibitory action of IFN-gamma on IL-4 signaling. These results suggest that SOCS-1 deficiency-induced persistent activation of STAT1 and STAT6, which would be inhibited by SOCS-1 under normal conditions, may induce abnormal activation of NKT cells, thus leading to lethal pathological changes in SOCS-1-deficient mice.

Toxicity and mutagenesis of chrysotile asbestos to Agrobacterium radiobacter

The mutation of Agrobacterium radiobacter cells exposed to chrysotile asbestos was examined by the random amplified polymorphic DNA (RAPD) method. Approximately 1.4 kbp of DNA in A. radiobacter, which was not amplified strongly in the cells that were not exposed to asbestos, was amplified in the cells that were exposed to asbestos. Mutation in genomic DNA of A. radiobacter was found to be induced by asbestos. Specific DNA that was amplified by asbestos present in PCR products and that which exists latently in genomic DNA were cloned, and these sequences were then determined and compared. It was shown that one of the mutations by the asbestos in the A. radiobacter occurred only in the primer annealed region and was a point mutation or deletion.

Involvement of angiotensin II in progression of renal injury in rats with genetic non-insulin-dependent diabetes mellitus (Wistar fatty rats)

Wistar fatty (WF) rats have a genetic predisposition to hyperglycemia, polyuria, hyperinsulinemia, hyperlipidemia, obesity and nephropathy. These phenotypic characteristics are similar to those observed in obese patients with non-insulin-dependent diabetes mellitus (NIDDM) nephropathy. In this study, the effects of two types of renin-angiotensin system inhibitors, an angiotensin II type 1-receptor antagonist (AT1A) and an angiotensin I-converting enzyme inhibitor (ACEI), on renal injury in WF rats were studied during the progressive phase of diabetic nephropathy. An AT1A, candesartan cilexetil (1 mg/kg), and an ACEI, enalapril (10 mg/kg), were administered orally once a day for 12 weeks, beginning when the rats were 27-week-old and already showed diabetic nephropathy and obesity. Both drugs prevented an increase in proteinuria during the experimental period. Furthermore, after 4-week intervention, the levels of proteinuria were markedly lower in drug-treated rats. At the end of the experiment, both drugs prevented the development of glomerular lesions without affecting glucose metabolism and obesity. In conclusion, the inhibition of angiotensin II activity ameliorated both existing proteinuria and the progression of proteinuria, resulting in preservation of glomerular structure. Thus angiotensin II plays important roles in the development and the progression of nephropathy in genetically obese diabetic WF rats.

Proposal of Sphingomonas wittichii sp. nov. for strain RW1T, known as a dibenzo-p-dioxin metabolizer

A polyphasic taxonomic study was performed on Sphingomonas sp. strain RW1T. The organism was isolated from water of the River Elbe and has been known as a potent metabolizer of dibenzo-p-dioxin and its relatives. TLC of a mild alkaline hydrolysate of extractable cellular lipids of strain RW1T and type strains of 21 Sphingomonas species gave a spot of sphingoglycolipid (SGL)-1 (glucuronosyl ceramide), which is characteristic of sphingomonads. In addition, strain RW1T and type strains of three Sphingomonas species (Sphingomonas yanoikuyae, Sphingomonas terrae and Sphingomonas macrogoltabidus) showed a second spot of SGL (SGL-1') identified as galacturonosyl ceramide. The presence of SGL-1 in cellular lipids suggested that strain RW1T is a member of the genus Sphingomonas. DNA-DNA reassociation rates between strain RW1T and each type strain of 14 Sphingomonas species including Sphingomonas paucimobilis, type species for the genus, revealed that strain RW1T is independent from these species. Results of phylogenetic analysis of 16S rDNA sequences of strain RW1T and type strains of 21 named Sphingomonas species verified that strain RW1T belongs to the genus Sphingomonas. Strain RW1T could be differentiated from named species of the genus by phenotypic characteristics and has been assigned to a new species, Sphingomonas wittichii sp. nov. The type strain is DSM 6014T (= JCM 10273T = EY 4224T). DNA G+C content is 67 mol %.

Novel non-peptide GPIIb/IIIa antagonists: synthesis and biological activities of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiperazinyl] acetic acids

To improve the in vitro and in vivo potency of our first low molecular weight GPIIb/IIIa antagonist 1 (TAK-029), a series of 2-[4-[2-(4-amidinobenzoylamino)-2-(substituted)acetyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiper-azinyllacetic acids were synthesized through modification of the glycine moiety of 1 and evaluated for their ability to inhibit in vitro adenosine 5'-diphosphate (ADP)-induced platelet aggregation of guinea pig platelet rich plasma (PRP). Among the compounds examined, the (3S,2S)-4-methoxyphenylalanine derivative 4h showed the most potent antagonistic activity with an IC50 value of 13 nM. Dose-dependent inhibition of ex vivo platelet aggregation was achieved with oral administration of 4h (0.3-1.0 mg/kg) to guinea pigs. Complete inhibition was observed for up to 8 h, and 43% inhibition could still be observed 24 h after oral administration of 1.0 mg/kg. The long-lasting antiplatelet effect of 4h suggests that 4h would be suitable for once-a-day dosing. Structure-activity relationships (SAR) were examined in the series of the phenylalanine derivatives. An increase in the electron density around the 4-position of the phenyl ring of the phenylalanine moiety led to an increase in the antiplatelet activity, suggesting the existence of a hydrophobic and electrostatic interaction site in addition to the ionic binding sites in the GPIIb/IIIa.

Orally active GPIIb/IIIa antagonists: synthesis and biological activities of masked amidines as prodrugs of 2-[(3S)-4

To improve the in vivo potency of the potent GPIIb/IIIa antagonist 2-[(3S)-4-[(2S)-2-(4-amidinobenzoylamino)-3-(4-methoxyphenyl)propanoyl]-3-(2-methoxy-2-oxoethyl)-2-oxopiperazinyljacetic acid (4), the amidino group was converted to an oxadiazole ring, thiadiazole ring or substituted amidoxime group. These groups were expected to be metabolized to an amidino group in vivo. The compounds synthesized were evaluated for their potency to inhibit the ex vivo adenosine 5'-diphosphate (ADP)-induced aggregation of guinea pig platelets. Among the compounds examined, the methoxycarbonyloxyamidine 8a exhibited the most potent ex vivo inhibitory activity with a fast onset and prolonged duration of action after oral administration.

Proposal of Sphingomonadaceae fam. nov., consisting of Sphingomonas Yabuuchi et al. 1990, Erythrobacter Shiba and Shimidu 1982, Erythromicrobium Yurkov et al. 1994, Porphyrobacter Fuerst et al. 1993, Zymomonas Kluyver and van Niel 1936, and Sandaracinobacter Yurkov et al. 1997, with the type genus Sphingomonas Yabuuchi et al. 1990

Based on the results of phylogenetic analysis of the 16S rDNA sequences and the presence of N-2'-hydroxymyristoyl dihydrosphingosine 1-glucuronic acid (SGL-1) and 2-hydroxymyristic acid (non-hydroxymyristic acid in Zymomonas) in cellular lipids, a new family, Sphingomonadaceae, for Group 4 of the alpha-subclass of the class Proteobacteria is herein proposed and a description of the family is given. The family consists of six genera, Sphingomonas, Erythrobacter, Erythromicrobium, Porphyrobacter, Sandaracinobacter and Zymomonas. Thus, all the validly published and currently known genera in Group 4 of the alpha-subclass of Proteobacteria belong to Sphingomonadaceae fam. nov. Among them, type strains of two species, Porphyrobacter and Erythrobacter, Sandaracinobacter sibiricus and Sphingomonas ursincola, respectively, are facultatively photosynthetic due to bacteriochlorophyll (Bchl)-a. The type strains of two subspecies of Zymomonas mobilis are facultative anaerobes. The presence of SGL-1 together with the results of a phylogenetic analysis of the 16S rDNA sequences recommends a new criteria by which to define the new family Sphingomonadaceae. The type genus is Sphingomonas Yabuuchi et al. 1990.

Structure-activity relationship of mycoloyl glycolipids derived from Rhodococcus sp. 4306

Novel mycoloyl glycolipids with short carbon chains were isolated and purified from Rhodococcus sp. 4306, a soil origin of Actinomycetales. Their chemical structures were identified as trehalose 6,6'-dimycolate (TDM), trehalose 6-monomycolate, glucose 6-monomycolate, mannose 6-monomycolate and fructose 6-monomycolate. The length of carbon chains and number of double bonds of mycolic acids were C(34), C(36)and C(38)saturated, monoenoic and dienoic molecular species, which were much shorter than those of Mycobacterium tuberculosis (C(78-88)monoenoic and dienoic). Among them, only TDM could induce prominent granulomatous inflammation of the lung and spleen in mice. By contrast, other mycoloyl glycolipids induced mild lesions. The small-sized TDM of Rhodococcus possessed granulomatogenic activity, however, the toxicity was much lower than that of M. tuberculosis. Rhodococcal TDM was composed of mycolic acid with the shortest carbon chains, when compared to granulomatogenic TDM of Mycobacterium, Nocardia and Rhodococcus reported previously. Our results imply that rhodococcal TDM is a pathogenetic factor similar to that of M. tuberculosis, although rhodococcal TDM exhibits low toxicity.

[Angiotensin II receptor antagonists: candesartan cilexetil]

Blockade of the action of angiotensin II (AII) has long been a target for the development of novel antihypertensive agents. We recently discovered a novel class of potent nonpeptide AII receptor antagonists, benzimidazole-7-carboxylic acids including candesartan. Candesartan is a highly potent and insurmountable AII type-1 receptor (AT1)-selective antagonist. Structure-activity relationship (SAR) studies revealed that the adjacent arrangement of a lipophilic substituent, a tetrazolylbiphenylmethyl moiety and a carboxyl group was the important structural requirement for potent AII antagonistic activity. Especially, the presence of a carboxyl group at the 7-position was found to be essential for insurmountable antagonism. To improve bioavailability of candesartan, chemical modification was examined to yield candesartan cilexetil, a prodrug of candesartan. Candesartan cilexetil is a potent and long-acting blocker that, when given once a day to patients, provides effective 24 hr blood pressure control.