Synergistic effect of temperature and background counterions on ion-exchange equilibria

The effects of temperature and background counterions on ion-exchange selectivity for alkali metal ions and tetraalkylammonium ions on strongly acidic cation-exchange resins have been investigated using superheated water ion-exchange chromatography (SW-IEC). We have found out that alkali metal ions show reversal in the order of the distribution coefficient (K_D), from Li⁺ < Na⁺ < K⁺ < Rb⁺ in water at ordinary temperature to Rb⁺ < K⁺ < Na⁺ < Li⁺ in superheated water, when a relatively large cation such as cesium ion is used as the background counterion. The effect of counterion on the ion-exchange selectivity is enhanced with the ion-exchange resins of higher ion-exchange capacity and cross-linking degree. Tetraalkylammonium ions chosen as model ions for poorly hydrated ions also exhibit reversal in the order of K_D at around 430 K in superheated water. However, the effect of the nature of alkali metal counterions on the change in K_D values of tetraalkylammonium ions is rather small compared with the effect on the K_D of alkali metal ions. These results are attributed to the change in local hydration structures of the ions in the ion-exchange resin due to dehydration of alkali metal ions enhanced by interionic contacts of the analyte ion with the coexisting counterion and lower hydration energy of the ions at elevated temperatures. Although it has been considered that temperature is not effective at changing the ion-exchange separation selectivity, significant selectivity changes can be achieved by SW-IEC.

Metal ions in cation-exchange resins are dehydrated by interionic contacts with a co-existing counterion at elevated temperatures, which causes a drastic change in separation selectivity.     

Increased DNA-incorporated thiopurine metabolite as a possible mechanism for leukocytopenia through cell apoptosis in inflammatory bowel disease patients with NUDT15 mutation

Journal of Gastroenterology - Polymorphisms in the nucleotide diphosphate-linked moiety X-type motif 15 (NUDT15) gene are associated with thiopurine-induced leukopenia in patients with inflammatory...     

Laparoscopy-assisted spleen-preserving distal pancreatectomy with conservation of the splenic artery and vein

Herein, we report the successful performance of a laparoscopy-assisted spleen-preserving distal pancreatectomy with conservation of the splenic artery and vein for a patient with pancreatic cystadenoma, as a minimally invasive procedure with the preservation of function. The laparoscopy-assisted distal pancreatectomy procedure involved detaching the spleen and the distal pancreas from the retroperitoneum by a hand-assisted procedure, removing them from the peritoneal cavity through a small incision, and detaching the distal pancreas by ligating and transecting the short gastric artery and vein and the branches of the splenic artery and vein, while the spleen and main splenic artery and vein were preserved under direct view. The pancreatic parenchyma was transected with a stapling device (TL-30), and continuous suturing was added to the resected margin. The patient’s postoperative course was uneventful; the patient started to eat and walk on postoperative day 2 and was discharged on day 8. It is considered that the combination of hand-assisted and laparoscopy-assisted distal pancreatectomy, with conservation of the splenic artery and vein, is a minimally invasive and clinically useful technique for treating tumors of cystic disease of the pancreas with low-grade malignant potential, or benign solitary neuroendocrine tumors.     

Direct demonstration of the cross-bridge recovery stroke in muscle thick filaments in aqueous solution by using the hydration chamber

Despite >50 years of research work since the discovery of sliding filament mechanism in muscle contraction, structural details of the coupling of cyclic cross-bridge movement to ATP hydrolysis are not yet fully understood. An example would be whether lever arm tilting on the myosin filament backbone will occur in the absence of actin. The most direct way to elucidate such movement is to record ATP-induced cross-bridge movement in hydrated thick filaments. Using the hydration chamber, with which biological specimens can be kept in an aqueous environment in an electron microscope, we have succeeded in recording ATP-induced cross-bridge movement in hydrated thick filaments consisting of rabbit skeletal muscle myosin, with gold position markers attached to the cross-bridges. The position of individual cross-bridges did not change appreciably with time in the absence of ATP, indicating stability of time-averaged cross-bridge mean position. On application of ATP, individual cross-bridges moved nearly parallel to the filament long axis. The amplitude of the ATP-induced cross-bridge movement showed a peak at 5–7.5 nm. At both sides of the filament bare region, across which the cross-bridge polarity was reversed, the cross-bridges were found to move away from, but not toward, the bare region. Application of ADP produced no appreciable cross-bridge movement. Because ATP reacts rapidly with the cross-bridges (M) to form complex (M·ADP·Pi) with an average lifetime >10 s, the observed cross-bridge movement is associated with reaction, M + ATP → M·ADP·Pi. The cross-bridges were observed to return to their initial position after exhaustion of ATP. These results constitute direct demonstration of the cross-bridge recovery stroke.     

A Case Report of an Adult With Severe Hyperlipidemia During Acute Lymphocytic Leukemia Induction Therapy Successfully Treated With Plasmapheresis

Plasmapheresis for the treatment of hypertriglyceridemia has previously been performed in patients with sudden onset severe hypertriglyceridemia and acute pancreatitis; however, only a few reports of this procedure have been published. We report here on a case showing severe hypertriglyceridemia during asparaginase (Asp) treatment for acute lymphocytic leukemia (ALL), and give an overview of a lipid‐lowering apheresis therapy. To prevent the complication of pancreatitis due to hypertriglyceridemia, we performed plasma exchange (PE) three times using fresh frozen plasma. PE remarkably reduced both serum triglyceride and total cholesterol levels from 5430 mg/dL to 403 mg/dL and from 623 mg/dL to 204 mg/dL, respectively. The causes of severe hyperlipidemia in this patient were considered to include: the Asp treatment for ALL, and a genetic background with a heterozygote of familial lipoprotein lipase (LPL) defect syndrome, because the patient's plasma LPL level after intravenous heparin injection was low at 137 ng/mL. Hence, PE using fresh frozen plasma may be useful not only to remove lipoproteins, but also to supply defective factors, such as LPL, in similar cases.     

A case of pulmonary embolic metastasis of choriocarcinoma presenting with multiple pulmonary infiltrative shadows]

A 34-year-old woman visited our hospital complaining of dry cough. Chest radiography and computed tomography showed bilateral multiple infiltrative shadows over the lung field. After an initial diagnosis of pneumonia, antibiotics were administered, but the therapy failed to improve the symptoms and abnormalities observed on the chest radiograph. The patient was then admitted to our hospital. The bronchoalveolar lavage fluid (BALF) was slightly bloody, but we were not able to make any specific findings in BALF. In order to confirm the pathological diagnosis, video-assisted thoracoscopic lung biopsy was performed aiming at the right middle and lower lobes. There were bleeding pulmonary infarctions in a biopsy specimen from the right middle lobe. Atypical cells positive for human chorionic gonadotropin (hCG) proliferated in the pulmonary arteries, and so a diagnosis of pulmonary embolic metastasis of choriocarcinoma was made. After the diagnosis, it became clear that urine and serum hCG values were very high. The patient has since received systemic chemotherapy in the gynecology unit at our hospital. Pulmonary embolic metastasis of choriocarcinoma diagnosed by video-assisted thoracoscopic lung biopsy has never been reported in the literature. However, early hCG measurement may have detected this syndrome in the earlier stages, and pulmonary metastasis of choriocarcinoma should be considered in the differential diagnosis of women with past pregnancy presenting with intractable multiple pulmonary shadows.     

A guinea pig model for cough variant asthma and role of tachykinins

Cough variant asthma is known as a major cause of chronic cough. Fundamental features of cough variant asthma are prolonged nonproductive cough responding to bronchodilator therapy, no history of wheezing or dyspnea attack, normal cough sensitivity, and slightly increased bronchial responsiveness. Animal model of cough variant asthma has not been reported. The aim of this study was to establish an animal model for studying detailed pathophysiology of cough variant asthma. Bronchial responsiveness to methacholine and cough reflex sensitivity to capsaicin were measured 72 hours after antigen (ovalbumin, OA) inhalation in actively sensitized guinea pigs. Next, cough number and specific airway resistance (sRaw) were measured during 20 minutes following reinhalation of OA solution, which was carried out 72 hours after the first OA inhalation, and then total cell number and cell differentials in bronchoalveolar lavage fluid (BALE) were measured. Bronchial responsiveness to methacholine, but not cough reflex sensitivity to capsaicin, was significantly increased 72 hours after the first inhalation of OA solution. Number of coughs, sRaw and total cell number in BALF increased significantly by the OA reinhalation, and the cough number and the increase in sRaw were significantly suppressed by beta2 agonist, procaterol. FK224, a specific neurokinin (NK) receptor antagonist, did not significantly influence the OA reinhalation-induced cough and increase in sRaw and total cell number in BALF in this model In conclusion, pathophysiologic feature of this animal model is similar to that of clinical cough variant asthma. Tachykinins may not play an important part in antigen-induced cough associated with bronchoconstriction and airway inflammation in cough variant asthma.     

Flowcharts for the management of biliary tract and ampullary carcinomas

No strategies for the diagnosis and treatment of biliary tract carcinoma have been clearly described. We developed flowcharts for the diagnosis and treatment of biliary tract carcinoma on the basis of the best clinical evidence. Risk factors for bile duct carcinoma are a dilated type of pancreaticobiliary maljunction (PBM) and primary sclerosing cholangitis. A nondilated type of PBM is a risk factor for gallbladder carcinoma. Symptoms that may indicate biliary tract carcinoma are jaundice and pain in the upper right area of the abdomen. The first step of diagnosis is to carry out blood biochemistry tests and ultrasonography (US) of the abdomen. The second step of diagnosis is to find the local extension of the carcinoma by means of computed tomography (CT), magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), percutaneous transhepatic cholangiography (PTC), and endoscopic retrograde cholangiopancreatography (ERCP). Because resection is the only way to completely cure biliary tract carcinoma, the indications for resection are determined first. In patients with resectable disease, the indications for biliary drainage or portal vein embolization (PVE) are checked. In those with nonresectable disease, biliary stenting, chemotherapy, radiotherapy, and/or best supportive care is selected.