The effect of 2,4,6,8-tetramethyldecanoic acid on the hydrolysis and acylation of phospholipid by lipase in isooctane

The effect of an unusual natural fatty acid, 2,4,6,8-tetramethyldecanoic acid (TMDA), on the hydrolysis and acylation of phospholipid by lipase in isooctane was studied. Lipases examined were fromRhizopus delemar, Candida cylindracea andPseudomonas sp. The lipase was dispersed in isooctane by dioleoylphosphatidylethanolamine (DOPE) with or without the fatty acid and decanoyl-lysophosphatidylcholine (LPC). The effect of TMDA on both the hydrolysis of DOPE and the acylation of LPC was compared with that of decanoic acid (DA) by varying the water content. At the higher water content, the hydrolysis of DOPE was enhanced or trace amount of phosphatidylcholine was produced. Hydrolysis was enhanced more by the addition of TMDA than by DA. The effect of TMDA on the acylation of LPC was similar to that of DA.     

Temporary extracorporeal axillofemoral venous bypass--a beneficial device in operation for superior vena caval syndrome due to intrathoracic malignancies

Life-threatening complications can occur unexpectedly during general anesthesia in operations for superior vena caval (SVC) syndrome due to intrathoracic tumors. To prevent such sequelae, we have placed a temporary extracorporeal axillofemoral venous bypass graft with satisfactory results. In six patients (malignant mediastinal tumor, four; lung cancer, two), under local anesthesia before induction of general one, the cannulas, each appropriately sized in accordance with the diameter of the axillary and femoral veins, were directly introduced into the corresponding veins after systemic heparinization. The two cannulas were connected with a tube to which a side arm, which was usually clamped, was connected. The venous pressure of the internal jugular vein decreased immediately after establishment of the temporary bypass in all patients. The symptoms that accompanied SVC syndrome did not worsen and the life-threatening complications at the time of induction of general anesthesia were avoided with this procedure. In each case cardiopulmonary bypass on stand-by was unnecessary at this time. Venous bypass grafting with vascular prostheses were mainly performed under cardiopulmonary bypass, which was required for such operative procedures. In three patients the side arms were used for part of the venous drainage during cardiopulmonary bypass. The SVC syndrome instantly disappeared after operations in all patients including one in hospital death. No serious complications related to the temporary bypass procedure have been observed. This temporary bypass procedure has several advantages. It can be safely performed under local anesthesia with no special technique for the cannulation. Venous blood naturally drains from the upper part to the lower part of the body by pressure gradient, that warrants the safe induction of general anesthesia and ensuing operative procedures. The side arm is available for venous drainage during cardiopulmonary bypass. There are no serious complications related to the bypass procedure. Thus this temporary bypass is recommended as a life-saving and auxiliary device in urgent operations for acute progressive SVC syndrome with symptoms of cerebral edema and upper airway obstruction due to intrathoracic malignancies.     

Moment analysis of stereoselective biliary excretion and chiral inversion of ketoprofen enantiomers in perfused rat liver

The stereoselective local disposition of ketoprofen was evaluated by the single-pass perfusion experiment following a bolus injection of R(-)- or S(+)-ketoprofen into the liver from the portal vein. The elution time profiles of enantiomers into the hepatic vein and the excretion time profiles into the bile were kinetically assessed by local moment analysis. The hepatic recovery ratios (FH) of both enantiomers were < 1%, and the mean hepatic transit times (tH) were approximately 7 s. After the injection of S-ketoprofen into the liver, the biliary excretion ratio (Fb) of total S-ketoprofen was 68% (15% S-ketoprofen and 53% glucuronide) and the mean biliary transit time (tb) of S-ketoprofen was 10 min. R-Ketoprofen inversion from S-ketoprofen was not observed in either the perfusate or in the bile. After the injection of R-ketoprofen, the Fb of total R-ketoprofen was 12% (3% R-ketoprofen and 9% glucuronide), and tb of R-ketoprofen was 8 min. The Fb of total S-ketoprofen inverted from R-ketoprofen was 24% (7% S-ketoprofen and 17% glucuronide), and the tb of inverted S-ketoprofen was 17 min. Forty-six percent of R-ketoprofen was inverted to S-ketoprofen during a single pass through the rat liver, and the mean inversion time was 7.5 min. It was concluded that the unidirectional chiral inversion of ketoprofen was stereospecific, and the hepatic uptake and biliary excretion were stereo-nonspecific.     

The distribution of afferent neurons in the trigeminal mesencephalic nucleus and the central projection of afferent fibers of the mylohyoid nerve in the rat

Horseradish peroxidase conjugated to wheatgerm agglutinin (HRP:WGA) was injected into the proximal cut ends of three branches of the mylohyoid nerve in rats: the branch to the mylohyoid muscle (BrMh), the branch to the anterior belly of the digastricus muscle (BrDg), and the cutaneous branch (BrCu). HRP-labeled cells were detected in the ipsilateral caudal portion of the trigeminal mesencephalic nucleus (Vmes) and the ipsilateral ventromedial division of the trigeminal motor nucleus, except when HRP:WGA was applied to the BrCu. Morphologically, all labeled Vmes cells were of the pseudounipolar type. Projections of the primary afferents of the BrMh were observed in the ipsilateral trigeminal nucleus caudalis, the upper cervical dorsal horns of laminae I-III, and the dorsolateral recticular formation (Rf), whereas the primary afferents of the BrDg terminated in the ipsilateral trigeminal nucleus principalis and Rf. These observations suggest that the role of the afferent inputs of the mylohyoid muscle differs from that of those of the anterior belly of the digastricus muscle in terms of several functions associated with jaw-closing and infrahyoid muscles.     

In vitro interaction between gingival fibroblasts and various root surfaces

The objective of the present in vitro study was to examine the effect of various root surface treatments on the initial attachment of gingival fibroblasts. Cultured fibroblasts were well spread and attached to demineralized dentin with citric acid, superficially curetted cementum, and root surface with periodontal ligament, while those on the planed dentin showed a poorly spread appearance. The first three root surfaces exhibited rough and irregular surface appearances with a well-developed filopodia and the latter root surface exhibited a smooth appearance, suggesting the texture of the root surface is closely associated with cell attachment. Interiorized collagen fibrils and numerous cytoplasmic vesicles were seen along the cell membrane of fibroblasts facing the root surfaces of the planed dentin, demineralized dentin, and superficially curetted cementum. Thus even the artificially exposed tooth surface with citric acid may be subjected to further alteration by fibroblasts.     

Linkage analysis in familial Alzheimer disease: description of the Duke and Boston data sets

Familial Alzheimer diseases is a neurological disorder of adult onset. Three research centers have each contributed their families and genetic linkage data for combined analyses. The data from the Duke and Boston centers, comprising 73 pedigrees for whom numerous markers on chromosomes 19 and 21 were typed are described.     

Pharmacokinetic analysis program based on tank-in-series model, MULTI(TIS), for evaluation of capacity-limited local disposition

A pharmacokinetic analysis program based on a tank-in-series model, MULTI(TIS), was developed for the evaluation of dose-dependency in the local disposition of a drug. The program written in FORTRAN was constructed by expanding MULTI(RUNGE). The reliability of MULTI(TIS) was verified by analyzing the experimental data based on linear and nonlinear tank-in-series models. Linear one- and two-compartment tank-in-series models were adopted to analyze outflow time profiles in single-pass hepatic perfusion following a pulse input of 5'-deoxy-5-fluorouridine (DFUR). The estimated parameters agreed well with those by MULTI(FILT) which is widely used for linear kinetic analysis. The nonlinear models adopted were one-compartment model with Michaelis-Menten elimination and two-compartment models with Michaelis-Menten elimination from central and peripheral compartments. Oxacillin was used as a model drug, because time courses of oxacillin show a capacity-limited hepatic disposition following a pulse input in high doses to the liver (300, 1000, 3000 and 5000 microg). The hepatic recovery ratio (F(H)) of oxacillin increased with dose, whereas the mean transit time (tH) was almost constant. The maximum elimination rate constant (Vmax) and Michaelis constant (Km) of oxacillin were estimated to be 1980 microg/ml/min and 54.1 microg/ml, respectively. Thus, the reliability of MULTI(TIS) was demonstrated for the analysis of nonlinear local disposition, especially, capacity-limited elimination in the liver.     

The ratio of reduced glutathione/oxidized glutathione is maintained in the liver during short-term hepatic hypoxia

Controversy persists as to whether reperfusion-induced injuries actually occur in the hepatocyte. The liver is the major source of glutathione, a scavenger of hydrogen peroxide. The aim of this study was to evaluate the sensitivity of the ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) [GSH:GSSG] as an index of hepatic metabolic stress. A total of 121 rats were studied. The superior mesenteric vein (SMV) was occluded for 30 min, and this was followed by 0, 10, or 120 min of reperfusion. Total glutathione and GSSG levels in the liver, bile, and plasma were quantified, using glutathione reductase-coupled enzymatic assays. Results indicated that the hepatic GSH/GSSG ratio was maintained after an occlusion of the SMV, despite a decrease in adenosine triphosphate (ATP) level and energy charge potential. However, plasma levels of total glutathione and GSSG in the inferior vena cava increased after SMV occlusion and continued to increase after reperfusion. Biliary GSSG efflux decreased during 30-min occlusion of the SMV, and remained low even after reperfusion. The liver maintains homeostasis despite a decrease in biliary GSSG efflux, probably by secreting excess GSSG into the hepatic vein when the SMV is occluded. We conclude that the total amount of glutathione and GSSG in the plasma is directly correlated with oxidative stress in the liver.     

Effect of lightning overvoltages on low-voltage power distribution lines due to direct lightning hits to overhead ground wire

Overhead ground wires and surge arresters have been installed to protect high-voltage power distribution lines and apparatus from overvoltages induced by nearby lightning strokes. The effects of surge arresters for protection of high-voltage distribution lines against direct lightning strokes have already been investigated using the digital simulation program EMTP (Electromagnetic Transients Program). With regard to the protection of low-voltage distribution lines from overvoltages induced by lightning strokes, experimental analyses using a scale model line have been reported. This paper reports on the comparison between the experimental analyses and EMTP simulation of power distribution lines, including low-voltage lines, and the validity of EMTP simulation. Furthermore, this paper analyzes the overvoltages on low-voltage power distribution lines against direct lightning strokes to overhead ground wire using the digital simulation.