A comparison of 7 types of epidural catheters

The stiffness on bending of 7 types of epidural catheters was measured with the help of a cantilever beam. 1415 patients scheduled for lithotripsy, requiring epidural anesthesia, were selected and randomly assigned to receive one of the catheters. The patients were divided into 2 groups according to the resistance to insertion. The incidence of intravenous insertion, subarachnoid location and paresthesia during catheter insertion were assessed. The position of epidural catheters was studied radiographically in 1276 of 1415 patients. There were no significant difference among 7 types of epidural catheters as far as the incidence of intravenous insertion, subarachnoid insertion or straight lying of catheter in epidural space were concerned. When the catheter was hard or pushed against the resistance to insertion, the incidence of paresthesia increased. When the catheter was hard and pushed against the resistance to insertion, transforaminal escape increased. A soft catheter should be chosen to minimize the incidence of paresthesia or transforaminal escape.     

Denture mobility with six degrees of freedom during function

SUMMARY The purpose of this study was (1) to assemble and verify a system to measure the three‐dimensional (3‐D) movement of the upper and lower complete dentures and the movement of the mandible simultaneously, and (2) to analyse the relation between denture movements and the path of closure of the mandible during function. A 3‐D motion capture system with four infrared TV cameras was used for this purpose. The relation between the dentures and the mandibular movements was analysed through the change of the inner product of normal vectors of the denture occlusal planes and mandibular planes. The mandibular movements were classified into two types the normal stroke (the path of closure was on the ipsilateral side of mastication) and the reverse stroke (on the contralateral side). The results showed that the system could measure the denture mobility within a 0·3 mm error. The mobility of the upper dentures had a correlation to the path of closure of the mandible regardless of the working side or nonworking side, and the lower dentures had a tendency to move toward the working side.     

The metabolism of peptide leukotrienes in the lung may affect their coronary vasoconstrictive effect in anesthetized dogs

The deteriorative effect of peptide leukotrienes (LTs) on the coronary circulation are well known. On the other hand, it has been recognized that some of these prostanoids are metabolized in the pulmonary vascular bed. To clarify the influence of the metabolism of LTs in the lung on their effects to the coronary circulation, we compared the changes of coronary circulation parameters by leukotriene D4 (LTD4) and C4 (LTC4) administered (5 mcg/kg) into the right atrium (RA) and the left atrium (LA) in 8 mongrel dogs. After the administration of LTD4 and LTC4, significant reduction of coronary blood flow (LTD4-RA 65.8 +/- 3.4%, LTD4-LA 54.8 +/- 2.3%, LTC4-RA 64.3 +/- 3.9%, LTC4-LA 66.9 +/- 3.7%) and elevation of coronary vascular resistance (LTD4-RA 130.5 +/- 8.2%, LTD4-LA 157.3 +/- 6.1%, LTC4-RA 138.7 +/- 8.0%, LTC4-LA 129.5 +/- 10.1%) were recognized. The effect of LTD4, administered into the left atrium was significantly greater than that administered into the right atrium (p less than 0.05). The difference between right and left atrial administration was not statistically significant, although a tendency for the effect to be greater with right atrial administration than left was recognized. The LTC4 concentration in aortic blood measured by radioimmunoassay was significantly lower in right atrial administration than left (p less than 0.05). These results suggested that LTD4 was metabolized and inactivated in the lung during its passage through the pulmonary circulation, and LTC4 was not only inactivated but also converted to LTD4 and activated in the pulmonary vascular bed.(ABSTRACT TRUNCATED AT 250 WORDS)     

Study on the mechanism of an experimental immunological intrahepatic cholestasis model.

Tuberculin-sensitized guinea pigs were intravenously injected with heat-killed Propionibacterium acnes followed by an intravenous injection of purified protein derivatives 7 day later, resulting in the induction of intrahepatic cholestasis. Using this experimental model, the following results were obtained: (1) Both uptake and release of bile acid were inhibited in the hepatocytes prepared from the cholestasis guinea pigs. (2) The results of the erythritol clearance method indicated that the decrease in bile flow observed in the cholestasis guinea pigs was mostly attributable to the reduced bile excretion from the canaliculi. (3) The decrease in the formation of bile acid independent bile flow was the cause of the decrease in bile flow observed in the cholestasis guinea pigs. (4) There was no change in the permeability of the interhepatocellular tight junction in the cholestasis guinea pigs.     

Effect of natural panting frequency and cheek support on the plethysmographic determination of thoracic gas volume in patients with chronic obstructive pulmonary disease]

The authors studied the effects of natural panting frequency (NF) and the cheek support on the plethysmographic measurement of thoracic gas volume (TGV) in 8 normal subjects (non-smokers) and 46 patients with chronic obstructive pulmonary disease (COPD). The patients were divided into 2 groups according to the degree of airway obstruction (group I; specific airway conductance (SGaw) greater than 0.1 (n = 18), group II; SGaw less than 0.1 (n = 28)). TGV was measured with a pressure-type body plethysmograph (BP). NF was 2.00 +/- 0.43 Hz (mean +/- SD) in control subjects, 1.92 +/- 0.78 Hz in group I, and 1.39 +/- 0.59 Hz in group II, respectively, indicating lower NF in the patients with severe airway obstruction. In control subjects and group I, the differences between TGV at NF and at 0.5-1.0 Hz (TGVNF-TGV1.0) were -0.01 +/- 0.07L, and -0.06 +/- 0.16L, respectively, and cheek support did not alter the difference. On the other hand, in group II, the difference was slightly larger than other groups in spite of the lower NF, and this overestimation was abolished by cheek support (0.13 +/- 0.25L-----0.06 +/- 0.27L, p less than 0.05). These results suggest that, in patients with severe airway obstruction, TGVNF may be overestimated even if NF is relatively low. This overestimation may be mainly due to the extrathoracic airway compliance including the cheek.     

Hydrostatic pressur influences mRNA exprssion of trnsforming growth factor-β1 and heat shock protein 70 in chondrocyte-like cell line

The present study investigated the influence of hydrostatic prssure on the exprssion of cytokines and heat shock protein 70 in a chondrocyte-like cell line. Chondrocyte-like cells (HCS-2/8) were exposed to hydrostatic pressur by a special pressure apparatus. Total RNA for cytokines (interleukin-1β, basic fibroblast growth factor, insulin-like growth factor-I, and transforming growth factor-β1) and for heat shock protein 70 was extracted and was analyzed by a polymerase chain reaction method and Northern blotting. An assay for incorporation of [³⁵S]sulfate was performed to assess proteoglycan synthesis. The expression of transforming growth factor-β1 mRNA was enhanced after exposure to 5 Mpa of hydrostatic prssure and was reduced after 50 Mpa, whereas the expression of heat shock protein 70 was enhanced following exposure to 50 Mpa of hydrostatic pressure. The incorporation of [³⁵S]sulfate into the cultured cells increased following exposure to 1-5 Mpa of hydrostatic pressure and decreased following 10-50 Mpa of pressure. These results suggest that hydrostatic pressure at physiologic levels enhances the expression of transforkming growth factor-β mRNA in addition to increasing proteoglycan synthesis in chondrocytes and that excessively high hydrostatic pressure reduces the expression of transforming growth factor-β1 mRNA and increases the expression of heat shock protein 79 mRNA while decreasing proteoglycan synthesis.     

Ross procedure in an infant weighing 4.5 kg

A 6 month-old male infant (weight: 4.5 kg) with congenital aortic stenosis underwent aortic valve replacement with a pulmonary autograft (Ross procedure). The right ventricular outflow tract (RVOT) was reconstructed with a polytetrafluoroethylene (PTFE)-valved equine pericardial conduit. At the age of 5, re-RVOT reconstruction with an equine pericardial patch bearing a PTFE monocusp was required because of severe pulmonary stenosis resistant to 2 attempts of percutaneous transluminal pulmonary valvotomy. Currently, at the age of 8, the degree of aortic regurgitation is trivial and the pulmonary autograft is free of functional deterioration despite somatic growth.