Usefulness of exosome-encapsulated microRNA-451a as a minimally invasive biomarker for prediction of recurrence and prognosis in pancreatic ductal adenocarcinoma

BACKGROUND

MicroRNAs (miRNAs) encapsulated in the exosomes of plasma is of interest as stable and minimally invasive biomarkers for recurrence and prognosis in cancer patients. The aim of this study was to clarify the predictive and prognostic value of plasma exosomal microRNA-451a (miR-451a) in patients with pancreatic ductal adenocarcinoma (PDAC).

METHODS

Microarray-based expression profiling of miRNAs derived from exosomes in the plasma of six PDAC patients with UICC stage II was employed to identify a biomarker to distinguish between patients with and without recurrence. For validation analysis, plasma exosome samples of other 50 PDAC patients were measured by TaqMan MicroRNA assays.

RESULTS

In the miRNA microarray analyses, miR-451a showed the highest upregulation in the stage II patients who showed recurrence after surgery. In the relationship to pathological factors, exosomal miR-451a showed a significant association with tumor size and stage. The overall survival (OS) and disease-free survival rates (DFS) of the high exosomal miR-451a patients were significantly worse than those of the low miR-451a patients. In Cox proportional hazards model analysis, exsomal miR-451a showed significance to OS and DFS.

CONCLUSIONS

Plasma exosomal miR-451a levels may be a useful minimally invasive biomarker for the prediction of recurrence and prognosis in PDAC patients.

Prognostic impact of type of preoperative biliary drainage in patients with distal cholangiocarcinoma

BACKGROUND

Surgical results of patients with resected distal cholangiocarcinoma (DCC) were evaluated to elucidate prognostic impact of the type of preoperative biliary drainage (PBD).

METHODS

Eighty-eight patients with resected DCC were stratified into two groups according to the type of PBD: the percutaneous transhepatic biliary drainage (PTBD) group (n = 25) and the endoscopic biliary drainage (EBD) group (n = 63).

RESULTS

Overall 5-year survival rate of the patients in the PTBD group was poorer than in the EBD group (24% vs. 52%, P = 0.020). On univariate analysis, PTBD, pancreatic invasion, perineural invasion, and lymph node involvement were significant prognostic factors for poor overall survival. On multivariate analysis, PTBD was the only significantly independent prognostic factor for poor overall survival. The incidence of liver metastasis was significantly higher in the PTBD group than in the EBD group (32.0% vs. 13.3%, P = 0.034).

CONCLUSIONS

PTBD should be avoided as much as possible in patients with DCC since the patients who underwent PTBD had poorer overall survival and higher incidence of liver metastasis than those who underwent EBD.

Biweekly gemcitabine plus S-1 for locally advanced and metastatic pancreatic cancer: a preliminary feasibility study

BACKGROUND

Chemotherapy for unresectable pancreatic cancer should not only prolong survival but maintain quality of life, considering its limited life expectancy. To achieve these goals, biweekly gemcitabine plus S-1 was assessed in the clinical practice setting.

METHODS

Fifty-two patients with either locally advanced or metastatic pancreatic cancer who received biweekly gemcitabine plus S-1 as a first-line anti-cancer treatment were included in this study. Treatment delivery, toxicity, response, and survival were reviewed to assess the feasibility and efficacy.

RESULTS

The completion rate of treatment delivery was 95.1%, with relative dose intensity of 97.1% for gemcitabine and 97.3% for S-1. Overall, grade 3 or worse adverse events were rare, with hematologic toxicities occurring in 5.8%. The objective response rate was 30.8%, and more than a 50% reduction of CA19-9 was observed in 77.1%. Surgical conversion was completed with a margin-negative resection in four patients whose tumor had shrunk for at least 6 months. The median progression-free and overall survivals were 10.4 and 18.2 months, respectively. Reduction of CA19-9 was associated with longer survival.

CONCLUSIONS

Biweekly gemcitabine plus S-1 may be a good alternative to current standard chemotherapies for unresectable pancreatic cancer with less toxicity and less treatment burden without losing efficacy.

Valuable antiviral therapeutic options for the treatment of chronic hepatitis C patients with thrombocytopenia

Thrombocytopenia in patients with chronic hepatitis C may represent an obstacle for the initiation of antiviral treatment. The aim of this study was to evaluate factors predictive of successful pegylated interferon (PEG-IFN) α2b and ribavirin (RBV) treatment for patients with thrombocytopenia with no history of splenectomy or partial splenic embolization. One hundred and fifty-one chronic hepatitis C patients (genotype 1: n = 110, genotype 2: n = 41) with TCP (<100 × 10(9) /L) at baseline were enrolled. Pretreatment variables included interleukin 28B (IL28B) genotype (rs8099917) and homoeostasis model assessment of insulin resistance score (HOMA-IR). The kinetics of haemoglobin and platelets according to the inosine triphosphatase (ITPA) genotype (rs1127354) were investigated. Sustained virological response (SVR) was significantly more frequent in hepatitis C virus (HCV) genotype 2 (65.9%) than in genotype 1 (34.5%) patients (P < 0.0001). Multiple logistic regression analysis of HCV genotype 1 extracted IL28B TT genotype [odds ratio (OR) 5.97, P = 0.006] and HOMA-IR <2.5 (OR 7.14, P = 0.0016) as significant independent pretreatment predictors of SVR. The analyses of HCV genotype 2 showed that HOMA-IR was significantly related to SVR, but IL28B genotype was not. Patients with ITPA CC genotype showed a significant haemoglobin reduction and lower degree of platelets decrease than those with ITPA CA/AA genotypes. The most common reason for premature discontinuation of treatment was the development of hepatocellular carcinoma (n = 8, 5.3%). In conclusion, HOMA-IR is a useful predictor of SVR for patients with thrombocytopenia infected with HCV genotype 1 or 2 treated with PEG-IFNα2b and RBV. The inclusion of IL28B, ITPA genotypes and HOMA-IR adds valuable therapeutic information.

Evaluation of the effects of freeze-dried soybean curd intake on cholesterol levels using a novel biomarker

To evaluate the effects of freeze-dried soybean curd intake on serum cholesterol levels, we examined the subclasses of cholesterol for healthy adult volunteers who continued to eat a piece of freeze-dried soybean curd each day along with their ordinary diet for four weeks. Of 12 subjects, the soybean curd diet proved effective in 2 cases; small dense LDL (sd-LDL) cholesterol levels were significantly reduced in association with the decrease in LDL cholesterol levels. These results suggested that daily intake of freeze-dried soybean curd may lead to an improvement in cholesterol metabolism in subjects with originally higher cholesterol levels and that sd-LDL cholesterol can be a novel biomarker for evaluation of the cholesterol lowering-action of functional food.

Periventricular notch activation and asymmetric Ngn2 and Tbr2 expression in pair-generated neocortical daughter cells

To understand the cellular and molecular mechanisms regulating cytogenesis within the neocortical ventricular zone, we examined at high resolution the spatiotemporal expression patterns of Ngn2 and Tbr2. Individually DiI-labeled daughter cells were tracked from their birth in slice cultures and immunostained for Ngn2 and Tbr2. Both proteins were initially absent from daughter cells during the first 2 h. Ngn2 expression was then initiated asymmetrically in one of the daughter cells, with a bias towards the apical cell, followed by a similar pattern of expression for Tbr2, which we found to be a direct target of Ngn2. How this asymmetric Ngn2 expression is achieved is unclear, but gamma-secretase inhibition at the birth of daughter cells resulted in premature Ngn2 expression, suggesting that Notch signaling in nascent daughter cells suppresses a Ngn2-Tbr2 cascade. Many of the nascent cells exhibited pin-like morphology with a short ventricular process, suggesting periventricular presentation of Notch ligands to these cells.

Protective effect of sivelestat sodium (Eraspol) on postoperative lung dysfunction in patients with type A acute aortic dissection: a pilot study

AIM

The authors evaluated the protective effect of sivelestat sodium on postoperative lung dysfunction in patients with type A acute aortic dissection who underwent aortic arch surgery with cardiopulmonary bypass (CPB) under deep hypothermia with circulatory arrest (DHCA).

METHODS

Twelve patients with type A acute aortic dissection who underwent aortic arch replacement under CPB with DHCA and were pretreated with or without sivelestat sodium (sivelestat group, N.=7 patients; control group, N.=5 patients) were observed. The ratio of arterial oxygen tension to inspired oxygen fraction (P/F ratio) was measured as a parameter of pulmonary function before and after operation. The number of white blood cells was also counted as an index of inflammatory reaction before and after the operation.

RESULTS

The P/F ratio decreased significantly after operation in the control group. However, the P/F ratio was unchanged between before and after operation in the sivelestat group. The number of white blood cells tended to increase after operation in the control group, whereas it decreased significantly after operation in the sivelestat group.

CONCLUSION

The present study demonstrated the protective effect of sivelestat sodium on postoperative lung injury in patients with acute type A aortic dissection undergoing aortic arch surgery under CPB with DHCA.

Design, synthesis, and evaluation of non-steroidal farnesoid X receptor (FXR) antagonist

A series of substituted-isoxazole derivatives was prepared as candidate farnesoid X receptor (FXR) antagonists, based on our previously proposed ligand superfamily concept. Structure-activity relationship studies indicated that the shape and the structural bulkiness of the substituent at the 5-position of the isoxazole ring affected FXR-antagonistic activity. Compounds 15 g (5-substituent: 2-naphthyl) and 15 h (5-substituent: 4-biphenyl) were identified as potent antagonists with higher selectivity for FXR over progesterone receptor than the naturally occurring FXR antagonist GS. The 5-substituent is also a critical determinant of the characteristic corepressor recruitment profile of this class of FXR antagonists, though distinct mechanisms appear to be involved: 15 h stabilizes the corepressor-nuclear receptor interaction, while 15 g inhibits coactivator recruitment.

Diphenylmethane skeleton as a multi-template for nuclear receptor ligands: preparation of FXR and PPAR ligands

Novel, potent farnesoid X receptor (FXR) and peroxisome proliferator-activated receptor alpha (PPARalpha) agonists were obtained by using a diphenylmethane skeleton as a substitute for a steroid skeleton.

The effects of a herbal medicine (Mao-to) in patients with chronic hepatitis C after injection of IFN-beta

We found that a herbal medicine (Mao-to) relieves the side effects of interferon (IFN)-beta and the combination therapy improves the biochemical response rate. However, the exact mechanism by which Mao-to is effective remains to be established. We conducted a controlled trial to clarify the effects of Mao-to. The study was carried out in 18 patients with chronic hepatitis C, and we examined subjective symptoms, body temperature and cytokines such as interleukin (IL)-beta, IL-1receptor antagonist (ra), IL-6 and TNF-alpha. Each patient received 6 million units of IFN-beta intravenously. Mao-to was given orally just before, just after, and 1 hour after IFN administration. The control study was carried out 6 months after the combination therapy of Mao-to and IFN-beta. The scores for general malaise, arthralgia and discomfort were significantly lower in the combination group than in control group. Body temperature did not significantly differ between the two groups. Plasma IL-6 level and IL-1ra were significantly elevated in the combination group compared to control (P = 0.0057 and 0.0003, respectively). Mao-to did not affect plasma concentrations of IL-1beta and TNF-alpha. We considered the increment of IL-1ra caused by Mao-to is to be one of the key factors involved in reducing the flu-like symptoms accompanying IFN-beta and improving the biochemical response rate.

A comparative study between excess-dose users and regular-dose users of rhubarb contained in Kampo medicines

With prolonged use of rhubarb-containing Kampo medicines, some patients come to ask for high-dose rhubarb because of deteriorated reactivity to rhubarb. We divided patients into two groups in terms of rhubarb-dose, and compared clinical backgrounds between regular-dose group and excess-dose group. Patients who were treated with rhubarb-containing Kampo extracts (manufactured prescriptions) or Kampo formulae (decoctions) for more than 12 months were enrolled. These two groups were compared for age, sex, shape of stool, abdominal symptoms, existence of hemorrhoids, Kampo diagnosis of abdomen, past stimulant laxative use, duration of stimulant laxative use before the first administration of rhubarb, duration of rhubarb use in our hospital, and initial existence of stimulant pain caused by taking stimulant laxatives for the first time. No significant difference was shown between the two groups in terms of age, duration of stimulant laxative-use before the first prescription of rhubarb, shape of stool, abdominal symptoms, existence of hemorrhoids, or duration of rhubarb-use. However, most patients in the regular-dose group had initial stimulant pain of the abdomen upon taking stimulant laxatives for the first time, but most patients in the excess-dose group did not (p < 0.001). All patients except one in the regular dose group had the sign of "umbilical region tenderness on pressure", but half of the excess-dose group did not have it (p = 0.041). Based on these findings, the absence of "initial stimulant pain" and the absence of "umbilical region tenderness on pressure" may predict increasing or excess use of rhubarb, and long-term use of rhubarb should be discouraged more strongly in the patients without these signs.

The efficacy of a herbal medicine (Mao-to) in combination with intravenous natural interferon-beta for patients with chronic hepatitis C, genotype 1b and high viral load: a pilot study

Patients with chronic hepatitis C, with a high serum viral load (> or = 1 Meq/ml) and genotype 1b seem to be resistant to interferon (IFN) therapy. To evaluate the efficacy of a herbal medicine (Mao-to) in combination with natural IFN-beta for the treatment of these patients, eighteen Japanese patients were enrolled in this study. Every patient received 6 million units (MU) of IFN-beta intravenously daily for 8 weeks. Mao-to was given orally 3-4 times a day during the IFN-beta administration, Sixteen of the 18 patients (89%) became negative for serum HCV RNA at the end of treatment, but only 2 of them (11%) remained negative for the virus RNA at 6 months of follow-up. Serum ALT levels normalized in 17 patients (94%) at 2 weeks of follow-up after the cessation of therapy, and 11 patients (61%) retained normal ALT levels for more than 6 months of follow-up. This rate of biochemical response was high as compared with that of therapy with IFN-beta alone (19%) in the largest IFN-beta trial in Japan. Serum hyaluronic acid levels were decreased significantly from 147.0 +/- 110.5 ng/ml to 77.4 +/- 67.4 ng/ml in the sustained biochemical response group (P = 0.003). None of the patients needed to interrupt therapy because of side effects of IFN-beta. Thus, Mao-to administration together with IFN-beta treatment could increase the sustained biochemical response rate, and reduce liver fibrosis.

Depletion and deletion analyses of eucaryotic translation initiation factor 1A in Saccharomyces cerevisiae

Translation initiation factor eIF1A is a highly conserved, small, acidic protein that is required for cell growth in yeast. Biochemical studies in vitro implicate eIF1A in dissociating ribosomes, promoting methionyl-tRNA(i) binding to 40S ribosomal subunits, scanning of mRNAs and recognizing the AUG initiation codon. To elucidate the pleiotropic functions of eIF1A in vivo, the factor was depleted by placing its gene behind the repressible GAL1 promoter. After Saccharomyces cerevisiae cells were shifted to glucose medium, depletion of eIF1A was seen after 3-4 generations, corresponding with cessation of cell growth. Polysome profiles of the depleted strain showed ribosome run-off from mRNAs, indicating that eIF1A is involved in the initiation phase of translation. A decrease in free 40S ribosomes and an apparent increase in free 60S ribosomes were attributed to the formation of 40S subunit dimers. The result suggests that one of the functions of eIF1A is to prevent formation of 40S dimers. Mutant forms of eIF1A lacking either the positively charged N-terminal region or the negatively charged C-terminal region were constructed and tested for their ability to confer cell growth as the sole source of eIF1A. Either deletion supports cell growth, albeit at a slower rate, and causes a reduction in polysomes, although eIF1A lacking the N-terminal region is more deleterious. Therefore the charged terminal regions contribute to, but are not absolutely essential for, eIF1A function.

Overexpression of HUT1 gene stimulates in vivo galactosylation by enhancing UDP-galactose transport activity in Saccharomyces cerevisiae

Transfer of activated sugar-nucleotides from the cytoplasm to the lumen of the Golgi is an essential requirement for glycosylation of glycoproteins, proteoglycans and glycosphingolipids. Although mannosylation is the major modification in the yeast Saccharomyces cerevisiae, several reports suggest the presence of galactose residues on yeast proteins and sphingolipids. We have detected alpha-galactosylated O-linked chitinase by lectin blotting from cells that functionally express the gma12(+) gene, encoding alpha 1,2-galactosyltransferase from Schizosaccharomyces pombe. This result implies the presence of a UDP-galactose transporter in S. cerevisiae. A conserved gene, HUT1, which encodes a putative multi-transmembrane protein, was cloned and characterized for its possible involvement in galactosylation. The HUT1 gene is not essential and is expressed at a relatively low level under the physiological conditions we examined. The disruption of this gene did not show any apparent impairments in glycosylation. However, a temperature- and concentration-dependent increase in UDP--galactose transport activity was detected from cells overexpressing HUT1 in the presence of gma12(+). The surface of these cells was confirmed to carry galactose residues by staining with FITC-conjugated alpha-galactose-specific lectin. These results suggest a role for Hut1p in the transport of UDP--galactose from the cytosol into the Golgi lumen in S. cerevisiae.

Coexpression of alpha1,2 galactosyltransferase and UDP-galactose transporter efficiently galactosylates N- and O-glycans in Saccharomyces cerevisiae

We have studied in vivo neo-galactosylation in Saccharomyces cerevisiae and analyzed the critical factors involved in this system. Two heterologous genes, gma12(+) encoding alpha1, 2-galactosyltransferase (alpha1,2 GalT) from Schizosaccharomyces pombe and UGT2 encoding UDP-galactose (UDP-Gal) transporter from human, were functionally expressed to examine the intracellular conditions required for galactosylation. Detection by fluorescence labeled alpha-galactose specific lectin revealed that 50% of the cells incorporated galactose to cell surface mannoproteins only when the gma12(+) and hUGT2 genes were coexpressed in galactose media. Integration of both genes in the Delta mnn1 background cells increased galactosylation to 80% of the cells. Correlation between cell surface galactosylation and UDP-galactose transport activity indicated that an exogenous supply of UDP-Gal transporter rather than alpha1,2 GalT played a key role for efficient galactosylation in S.cerevisiae. In addition, this heterologous system enabled us to study the in vivo function of S. pombe alpha1,2 GalT to prove that it transfers galactose to both N - and O -linked oligosaccharides. Structural analysis indicated that this enzyme transfers galactose to O -mannosyl residue attached to polypeptides and produces Galalpha1,2-Man1-O-Ser/Thr structure. Thus, we have successfully generated a system for efficient galactose incorporation which is originally absent in S. cerevisiae, suggesting further possibilities for in vivo glycan remodeling toward therapeutically useful galactose containing heterologous proteins in S. cerevisiae.

The 39-kilodalton subunit of eukaryotic translation initiation factor 3 is essential for the complex's integrity and for cell viability in Saccharomyces cerevisiae

Eukaryotic translation initiation factor 3 (eIF3) in the yeast Saccharomyces cerevisiae comprises about eight polypeptides and plays a central role in the binding of methionyl-tRNAi and mRNA to the 40S ribosomal subunit. The fourth largest subunit, eIF3-p39, was gel purified, and a 12-amino-acid tryptic peptide was sequenced, enabling the cloning of the TIF34 gene. TIF34 encodes a 38,753-Da protein that corresponds to eIF3-p39 in size and antigenicity. Disruption of TIF34 is lethal, and depletion of eIF3-p39 by glucose repression of TIF34 expressed from a GAL promoter results in cessation of cell growth. As eIF3-p39 levels fall, polysomes become smaller, indicating a role for eIF3-p39 in the initiation phase of protein synthesis. Unexpectedly, depletion results in degradation of all of the subunit proteins of eIF3 at a rate much faster than the normal turnover rates of these proteins. eIF3-p39 has 46% sequence identity with the p36 subunit of human eIF3. Both proteins are members of the WD-repeat family of proteins, possessing five to seven repeat elements. Taken together, the results indicate that eIF3-p39 plays an important, although not necessarily direct, role in the initiation phase of protein synthesis and suggest that it may be required for the assembly and maintenance of the eIF3 complex in eukaryotic cells.

Continuous urine oxygen tension monitoring in patients undergoing cardiac surgery

OBJECTIVES

To evaluate the effect of cardiopulmonary bypass (CPB) on urine oxygen tension (PuO2) and to determine whether perioperative PuO2 can predict postoperative renal dysfunction in patients undergoing cardiac surgery.

DESIGN

Prospective clinical study.

SETTING

A university research laboratory, a university-affiliated hospital.

PARTICIPANTS

Ninety-eight consecutive adult patients undergoing coronary artery bypass surgery or valvular surgery.

INTERVENTIONS

PuO2 was continuously measured by inserting a polarographic electrode into the urinary tube connected to a Foley catheter.

MEASUREMENTS AND MAIN RESULTS

PuO2 was constant before CPB and then progressively decreased after the start of CPB. It partially recovered at weaning from CPB but did not completely return to its original level until the end of surgery. Postoperative serum creatinine concentrations were significantly higher in patients whose PuO2 decreased after CPB, as compared with those whose PuO2 was constant or increased. The amplitude and the rate of recovery in PuO2 after CPB were significantly associated with peak values of postoperative serum creatinine concentrations.

CONCLUSIONS

These results suggest the possibility of PuO2 detecting an early stage of renal dysfunction in cardiac surgery, although further studies will be required to substantiate it.

Characterization of yeast translation initiation factor 1A and cloning of its essential gene

Translation initiation factor eIF1A is required in vitro for maximal rates of protein synthesis in mammalian systems. It functions primarily by dissociating ribosomes and stabilizing 40 S preinitiation complexes. To better elucidate its precise role in promoting the translation initiation process, the yeast form of eIF1A has been identified in Saccharomyces cerevisiae and purified to homogeneity on the basis of its cross-reaction with antibodies prepared against mammalian eIF1A. The apparent mass of yeast eIF1A (22 kDa) resembles that of the mammalian homolog (20 kDa), and the yeast factor is active in stimulating methionyl-puromycin synthesis in an assay composed of mammalian components. The gene encoding yeast eIF1A, named TIF11, was cloned and shown to be single copy. TIF11 encodes a protein comprising 153 amino acids (17.4 kDa); the deduced amino acid sequence exhibits 65% identity with the sequence of human eIF1A. Both human and yeast eIF1A contain clusters of positive residues at the N terminus and negative residues at the C terminus. Deletion/disruption of TIF11 demonstrates that eIF1A is essential for cell growth. Expression of human eIF1A cDNA rescues the growth defect of TIF11-disrupted cells, indicating that the structure/function of yeast and mammalian eIF1A is highly conserved.

The effect of dobutamine on hepatic blood flow and oxygen supply-uptake ratio during enflurane nitrous oxide anesthesia in humans undergoing liver resection

Liver surgery is often accompanied by hepatic hypoperfusion and hypoxia, and it is controversial whether catecholamines increase hepatic blood flow and oxygen supply. The effects of 3 micrograms.kg-1.min-1 dobutamine on hepatic circulation and oxygen balance were examined in patients anesthetized with enflurane, nitrous oxide, and oxygen for liver surgery. Dobutamine did not cause a significant increase in hepatic arterial blood flow. However, total hepatic blood flow and portal venous blood flow were increased, resulting in an increase in hepatic oxygen delivery (HDO2). The increase in HDO2 was not associated with an improvement of hepatic oxygen supply-uptake ratio, since hepatic oxygen uptake (HVO2) also increased. After hepatectomy, the increases in portal venous blood flow and HDO2 were not accompanied by an increase in HVO2. The stimulation of hepatocellular oxygen metabolism by dobutamine and depressed responsiveness of adrenoceptors on hepatocytes in which metabolism was already augmented are the likely explanation for the different reactions before and after hepatectomy.

Hepatic venous hemoglobin oxygen saturation predicts liver dysfunction after hepatectomy

A fiberoptic flow-directed catheter inserted into the hepatic vein continuously measures hepatic venous oxygen hemoglobin saturation (ShvO2). This study determined whether intraoperatively measured ShvO2 could predict postoperative serum activities of aminotransferases and patient outcome in 83 patients undergoing hepatectomy. The duration of intraoperative ShvO2 less than or equal to 10, 20, 30, 40, and 50% was calculated in each case. Significant increases in postoperative serum aminotransferases were associated with more than 1, 11, 31, 51, and 181 min of duration of ShvO2 less than or equal to 10, 20, 30, 40, and 50%, respectively. The incidence of postoperative liver failure significantly increased when the duration of ShvO2 less than or equal to 20, 30, and 40% exceeded 11, 31, and 51 min, respectively. The mortality from liver failure was significantly higher when the duration of ShvO2 less than or equal to 30 and 40% exceeded 31 and 51 min, respectively. Therefore, intraoperative monitoring of ShvO2 may predict not only the increase in postoperative serum aminotransferases but also patient outcome in terms of postoperative liver failure after hepatectomy.

Effect of acute changes in renal arterial blood flow on urine oxygen tension in dogs

The relationships between urine oxygen tension (PuO2), PaO2, and acute changes in renal arterial blood flow (RBF) were studied in 19 anesthetized dogs. Indwelling sensors that measure continuously PO2 were inserted into the femoral artery and the ureter. RBF was measured by an electromagnetic flowmeter placed over the renal artery. PuO2 increased significantly from 36 to 72 torr during a stepwise increase in PaO2 from 70 to 180 torr. RBF was decreased in a stepwise fashion from a baseline value of 5.51 to 4.16, 2.13, and finally to .20 ml/kg.min by aortic constriction. PuO2 decreased significantly from a baseline value of 72 torr to 66, 57, and finally to 23 torr. The correlation coefficient between RBF and PuO2 was .84, which was significantly higher than that between RBF and femoral arterial pressure or that between RBF and urinary flow rate. This study demonstrates that PuO2 is a sensitive indicator of acute RBF changes in normal, healthy dogs.

Electroporation-transformation system for coryneform bacteria by auxotrophic complementation

We evaluated electroporation as an alternative system for genetic exchange for one of the coryneform bacteria, Brevibacterium flavum MJ233. The maximum number of transformants, 6 x 10(4) cells, was obtained when cells were cultured with Penicillin G (1 U/ml) and harvested at the middle-log phase. Electroporation was done using 12.5 kV/cm of pulse field strength, 1 x 10(10) cells, and 1 microgram of plasmid DNA. Other coryneform bacteria, Brevibacterium lactofermentum ATCC 13869, Corynebacterium glutamicum ATCC 31830, and B. stationis IFO 12144 were also transformed by electroporation. Electroporation has the advantage that intact cells can be used as host cells without the need for protoplast formation and regeneration. Moreover, minimal medium can be used, so auxotrophic complementation of the transformants is possible.

Effects of isosorbide dinitrate on thromboxane A2 synthesis in carbon dioxide exposed platelets

Isosorbide dinitrate (Nitorol R, 100 nmol/l) blocked an increase in thromboxane B2 concentration in human platelet-rich plasma caused by exposure to high CO2 tension, in the presence of arachidonic acid. Thromboxane B2 concentrations obtained at 1 or 2 mmol/l or arachidonic acid were not influenced by isosorbide dinitrate at low CO2 tension. Inhibitory action of isosorbide dinitrate on the thromboxane A2 synthesis appears to have a close relation to the site of CO2 action.

Factors influencing fibrin-induced pulmonary edema

Effects of depth of anesthesia, pH of fibrinogen and thrombin, and interventions in the vagus nerves on the development of fibrin-induced pulmonary edema were examined in the rat. Rats were anesthetized with an intraperitoneal injection of pentobarbital sodium, 25 or 50 mg/kg. Solutions of fibrinogen and thrombin at the same pH were separately injected into the cisterna magna. The pH values were adjusted to 6.5 or 8.5 with Tris buffer. Interventions in the vagus nerves, which consisted of atropine administration at a dose of 1 mg/kg, i.v. or bilateral vagotomy, were performed before the intracisternal injection of fibrinogen and thrombin. Animals in which no interventions in the vagus nerve was performed were designated as intact rats. Lung-water ratio was calculated as a ratio of the difference between wet and dry lung weight to dry lung weight. Incidences of pulmonary edema and lung-water ratios were lower under deep anesthesia than under light anesthesia. Both parameters were low in the vagotomized rats treated under deep anesthesia with fibrinogen and thrombin at a pH of 8.5, as compared to those treated similarly at pH 6.5. This phenomenon was not observed under light anesthesia. Interventions in the vagus nerves influenced the development of pulmonary edema to various degrees, depending on the pH values of the injected fibrinogen and thrombin. As suggested from these results, well-defined, specific conditions are required for investigating the mechanism triggering the development of fibrin-induced pulmonary edema.

Use of pulse oximetry for monitoring tracheostomy tube obstruction

Experimental studies were performed on dogs for monitoring postoperative tracheostomy tube obstruction using a pulse oximeter. While a 25% obstruction of the cross-sectional area of the tube did not alter the oxygen saturation, obstruction of 40% and above resulted in a drop in the oxygen saturation level which corresponded to the degree of obstruction. The greater the degree of obstruction, the sooner was the fall of oxygen saturation. Therefore a pulse oximeter could be effectively put to use to monitor tracheostomy tube obstruction.

Isosorbide dinitrate blocks thromboxane synthesis caused by CO2 in dog heart-lung preparation

Effects of isosorbide dinitrate (ISDN) on coronary flow and arterial prostaglandin (PG) concentrations were investigated, using dog heart-lung preparations. Two kinds of gases (low and high CO2 gases) were used for the artificial respiration. Low CO2 gas contained 55% O2 and 0.2% CO2, whereas high CO2 gas contained 55% O2 and 8% CO2. Administration of ISDN into a blood reservoir at high CO2 caused an increase in coronary sinus blood flow, which was blocked by indomethacin, but not at low CO2. In the absence of ISDN, the arterial concentration of thromboxane (TX) B2 was larger at high CO2 than at low CO2. ISDN attenuated such an increase in TXB2 concentration caused by CO2. The arterial concentration of 6-keto PGF1 alpha was altered by neither CO2 nor ISDN, but slightly increased with time. Indomethacin lowered the concentrations of 6-keto PGF1 alpha and TXB2. These results suggested that the arterial CO2 tension enhanced the TXA2 synthesis and that ISDN inhibited such a relation between CO2 and TXA2 synthesis. Additionally, the vasodilatory effects of PGI2 was enhanced by elevating the arterial CO2 tension. Thus, the increase in canine coronary flow at high CO2 in the presence of ISDN may be related to the inhibitory effects of ISDN on the TXA2 synthesis enhanced by the high arterial CO2 tension and the facilitatory effects of CO2 on the PGI2-induced vasodilation.

Preoperative fiber-optic lung cancer detection. A case report

A case of unexpected detection of bronchial neoplasm in routine general anesthesia is described. On the basis of this case, fiber-optic bronchoscopy in all patients undergoing general anesthesia as a means of early detection of lung cancer is discussed.

Cervical epidural anaesthesia in carotid artery surgery

The successful anaesthetic management using a cervical epidural technique is reported in three patients undergoing carotid artery surgery. Adequate analgesia was obtained in all cases and the adequacy of cerebral blood flow was easily judged by the patient's state of consciousness. Cervical epidural anaesthesia could be a safe and reasonable technique for the management of patients who need carotid artery surgery.