Effect of mutual configuration between molecular orientation and atomic orientation in the oriented Ar (3P2)+oriented CF3H reaction

The steric effect in the dissociative energy transfer reaction of Ar (3P2,MJ=2)+CF3H has been observed as a function of the mutual configurations between the molecular orientation and the atomic orientation in the collision frame. The reactivity is significantly changed depending on the mutual configuration between the molecular orientation and the atomic orientation. Especially, the molecular alignment dependence is dramatically changed depending on the configuration of the atomic alignment.

Correlation between atomic orientation and product angular momentum alignment in the reaction of oriented Ar (3P2) with CH3OH

Atomic orientation effect for the CH(3)O(*) formation has been studied for the dissociative energy transfer reaction of oriented Ar ((3)P(2)) with CH(3)OH. The degree of polarization of CH(3)O(*) chemiluminescence was determined as a function of each magnetic M(J) (') substate in the collision frame. A drastic change of the product angular momentum alignment due to atomic orientation was recognized.

Significant change of alignment effect by dimer formation in the dissociative energy transfer reaction of Ar(3P2)+(N2O)n and (H2O)n

An alignment effect in the dissociative energy transfer reaction of Ar((3)P(2))+(X(2)O)(n)(X=N,H) was directly measured using an oriented Ar((3)P(2),M(J)=2) beam. The chemiluminescence intensity of N(2)(B,(3)Pi(g)) for (N(2)O)(n) and OH(A,(2)Sigma(+)) for (H(2)O)(n) was measured as a function of the magnetic orientation field direction in the collision frame. The relative reaction cross section for each magnetic substate in the collision frame, sigma(M(J) (') ), was determined. In both the reaction systems, it is observed that the dimer formation significantly enhances the alignment effect and decreases the reactivity, especially for sigma|1| and sigma|2|. A significant contribution of rank 4 moment is recognized in the dimer reaction.

Steric effect in the energy transfer reaction of Ar(3P2)+N2

Steric effect for N2(C,3Piu) formation in the energy transfer reaction of Ar(3P2)+N2 was directly measured by using an oriented Ar(3P2,MJ=2) beam at a collision energy of 0.06 eV. The N2(C,3Piu) chemiluminescence intensity was measured as a function of the magnetic orientation field direction in the collision frame. A significant alignment effect on the energy transfer probability was observed. The relative reactivity for each magnetic substate in the collision frame sigma|MJ'|was determined to be sigma|2|:sigma|1|:sigma(0)=0.50:0.60:1.00. It is suggested that the observed steric effect is primarily due to the favorable configuration of the 3p orbital for the efficient overlap with the 2sigma(u) molecular orbital of N(2).

Invasive growth of hepatic angiomyolipoma; a hitherto unreported ominous histological feature

AIMS

Although histological features of hepatic angiomyolipoma (AML) are highly variable, true malignant change is extremely rare. The aim was to review the histological features of invasive growth and clinical outcomes in 39 cases of hepatic AML.

METHODS AND RESULTS

An invasive growth pattern into surrounding hepatic parenchyma, portal triads and/or around hepatic veins was found in 24 of 39 tumours (62%). One variant showed tumour cells replacing hepatocytes within the liver cell cords. The other consisted of portal or perivascular invasive growth along blood vessels. In the former pattern, small isolated tumour cell clusters were occasionally found in the vicinity of the main mass, showing a sprouting pattern. Although these histological features suggest malignancy, distant metastases were not found in any of the cases within a mean follow-up period of 6.8 years.

CONCLUSIONS

A previously unrecognized histological feature of an invasive growth pattern, which suggests malignancy and might promote an erroneous diagnosis, was frequently found in hepatic AMLs. However, among about 180 reported hepatic AMLs, including the present cases, only one hepatic AML with distant metastasis has been reported to date and nearly all hepatic AMLs behave in a benign fashion. Therefore, pathologists should not overdiagnose malignancy based solely on the histological invasive growth patterns described in this paper.

The N-terminus of rodent and human MAD1 confers species-specific stringency to spindle assembly checkpoint

The spindle assembly checkpoint (SAC) guards against chromosomal mis-segregation and the emergence of aneuploidy. SAC in higher eukaryotes includes at least 10 proteins including MAD1-3, BUB1-3, and Msp1. A long-standing observation has been that rodent cells are more tolerant of microtubule toxins than primate cells indicating that SAC function is more relaxed in the former than the latter. Here, we report on an unexpected functional difference between the rodent and human MAD1 component of the respective SAC. Ectopic expression of human MAD1 in mouse and hamster cells corrected a relaxed SAC to a more stringent form. Our findings posit MAD1 as a species-specific determinant which influences the stringency of cellular response to microtubule depolymerization and spindle damage.

Induction of pancreatic trypsin by dietary amino acids in rats: four trypsinogen isozymes and cholecystokinin messenger RNA

We previously demonstrated that feeding a diet containing a high level of amino acid mixture simulating casein (AA) induced an increase in pancreatic protease activities in rats. In the present study, this effect of dietary AA was further characterized with three separate experiments. These experiments (1) examined periodic changes in pancreatic and small intestinal trypsin activities after switching from a 20% (a normal nitrogen level) AA diet to a 60% AA (a high nitrogen level) diet; (2) measured the abundance of mRNA for four trypsinogen isozymes and for intestinal cholecystokinin (CCK) and secretin in rats fed 20% and 60% AA diets for 10 days compared with rats fed 20% and 60% casein diets; and (3) measured the abundance of mRNA for four trypsinogen isozymes after chronic administration of CCK. Trypsin activities were gradually increased in both the pancreas and the small intestinal lumen and reached maximum at 5 days after the switch to the 60% AA diet (Exp. 1). This result is evidence that the increase in the protease activity in the pancreas is due to enhancement of pancreatic trypsin production. In experiment 2, pancreatic trypsinogen isozymes I, II, III, and IV mRNA abundance were evaluated by the Northern blotting method using cDNA probes specific for each isozyme mRNA. Abundance of trypsinogen mRNA without trypsinogen I tended to increase in the rats fed the 60% casein diet but tended to decrease in the rats fed the 60% AA diet compared with the respective normal nitrogen level diet groups without significant difference. CCK mRNA abundance in the jejunal mucosa increased as a result of feeding the 60% casein diet, but not the 60% AA diet. Subcutaneous CCK injections (3.5 nmole/kg body weight/day, twice daily, at 8:30 am and 7:30 pm) for 10 days resulted in increased pancreatic trypsin activity, whereas the changes in mRNA of the four trypsinogen isozymes was similar between the 20% and 60% casein groups but differed between the 20% and 60% AA groups (Exp. 3). These results suggest that CCK is not involved in the induction of pancreatic trypsin that occurs with feeding of a high AA diet and that the mechanism of protease induction by dietary AA is different from that in the case of dietary protein.

Influence of microcatheter length on flow rates of disposable infusion kits

BACKGROUND AND OBJECTIVE

Continuous spinal analgesia (CSA) offers considerable pain relief, and has been used in various procedures such as for surgery and cancer pain control. In Japan, portable and disposable infusion kits are increasingly employed for continuous epidural analgesia and CSA. In CSA, the use of a microcatheter is expected to reduce the incidence of spinal headache previously encountered with larger catheters. However, the flow rate of disposable infusion kits is reduced when used in conjunction with a microcatheter.

METHODS

This study aimed to investigate the influence of catheter length on the flow rate of two different devices: 20- or 91-cm 28-G microcatheters connected to balloon- or syringe-type infusion pumps were examined (50 mL, 1 mL h(-1)). There were four groups each of 10 experiments: Group A: balloon-type infuser, 91 cm catheter; Group B: balloon-type infuser, 20 cm catheter; Group C: syringe-type infuser, 91 cm catheter; Group D: syringe-type infuser, 20 cm catheter.

RESULTS

The mean flow rate in Group A was significantly less than that in Group B and the mean flow rate in Group C was significantly less than Group D (P < 0.05).

CONCLUSION

These results indicated that the use of a shorter microcatheter achieves a better flow rate during CSA.

Rotational state-resolved reaction cross section in the reactions of state-selected CH with NO and with O2

A pure and highly intense state-selected pulsed supersonic CH(X (2)Pi) radical beam source was developed by use of the C((1)D)+H(2) reaction with the combination of the state selection and purification by an electrostatic hexapole field. Under the beam-cell condition, the elementary reactions of CH+NO and CH+O(2) were studied by using this state-selected CH beam. NH(A (3)Pi) [and NCO(A (2)Sigma(+))] formations and OH(A (2)Sigma(+)) formation were directly identified in the elementary reaction of CH+NO and CH+O(2), respectively. For the CH+NO reaction, the relative branching ratio sigma(NCO*)sigma(NH) of NCO(A (2)Sigma(+)) formation to NH(A (3)Pi) formation was determined to be 0.35+/-0.15. The state-selected reaction cross sections were determined for each rotational state of CH. In the CH+NO reaction, a remarkable rotational state dependence of the reactive cross section was revealed, while the CH+O(2) reaction showed little rotational state dependence.

A repetitive, steady mouth opening induced an osteoarthritis-like lesion in the rabbit temporomandibular joint

Although excessive mechanical stress is assumed to be one of the factors contributing to pathogenesis of temporomandibular joint (TMJ) osteoarthritis (OA), no pure mechanical-stress-induced OA model has been developed without surgical manipulation or puncture of the joint cavity. The purpose of this study was to establish a genuine mechanical-stress-induced OA model of the rabbit TMJ. In the experimental rabbits, repetitive, forced jaw-opening, 3 hrs/day for 5 days, was applied with the use of a general anesthesia protocol. By histological assessment of the TMJ articular tissues, partial eburnation of the articular cartilage, reactive marginal proliferation of the articular cartilage chondrocytes, and nested proliferation of chondrocytes in the subchondral bone area were observed at 7 days after the repetitive, forced-jaw-opening period. These results suggest that the repetitive, forced-jaw-opening protocol without surgical intervention can induce evident OA-like lesions in the rabbit TMJ, and this OA model may greatly contribute to the elucidation of the cartilage degradation mechanism in TMJ OA.

Aseptic meningitis during combined continuous spinal and epidural analgesia

Continuous spinal analgesia (CSA) offers considerable advantages: (1) it requires 10% of the local anesthetic; (2) it may be instituted after patient positioning, thus minimizing the potential for cardiovascular instability; and (3) with low doses of dilute short-acting local anesthetic, the recovery period is shortened (1). Continuous spinal analgesia has been used for various procedures such as surgery and cancer pain control. However, CSA has not gained wide popularity because of its possible complications, such as headache, nerve injury, infection and accidental removal or migration of the catheter. Although real possibilities, these complications have been rarely documented. We describe an episode of aseptic meningitis during combined CSA and EA.

The vasoconstriction threshold is increased in obese patients during general anaesthesia

BACKGROUND

In anaesthetized patients, body temperature decreases often, but overweight patients become less hypothermic. Obesity in itself protects body heat, and thermoregulatory reflexes may maintain normothermia in obese patients. We tested the hypothesis that even slight obesity increases the vasoconstriction threshold.

METHODS

Twenty male patients aged 30-65 years scheduled for open abdominal surgery were allocated to two groups: body fat >/=25% (obese group, n = 10), or <25% (normal weight group, n = 10). Anaesthesia was maintained with 0.4% isoflurane and opioid. The thermoregulatory vasoconstriction threshold was defined by the tympanic membrane temperature at which the skin temperature gradient equalled 0 degrees C. Plasma adrenaline, noradrenaline and leptin were measured.

RESULTS

Age, height, heart rate and blood pressure did not differ between the two groups of patients. In the obese group the vasoconstriction threshold was higher than that in the normal weight group: 36.0 +/- 0.1 vs. 35.5 +/- 0.2 degrees C. Consequently, after 4 h of anaesthesia, the core temperature was highest in the obese patients: 36.4 +/- 0.1 vs. 35.5 +/- 0.2 degrees C.

CONCLUSIONS

These results suggest that core temperature is maintained in obese patients because their vasoconstriction threshold to a low environmental temperature is high.

Preoperative blood pressure and catecholamines related to hypothermia during general anesthesia

BACKGROUND

We previously demonstrated that preoperative blood pressure values affect intraoperative hypothermia during general anesthesia. We hypothesized that increased catecholamine secretion could be responsible for the relationship between preoperative blood pressure and hypothermia.

METHODS

To evaluate the effect of preoperative systolic blood pressure (SBP) and plasma catecholamine levels on core temperature during general anesthesia, 40 male patients who were scheduled for open abdominal surgery were allocated to two groups: those whose preoperative SBP was 140 mmHg or greater (high SBP group, n = 20), and those whose SBP was less than 140 mmHg (normal SBP group, n = 20). Anesthesia was maintained with 0.4% isoflurane and opioids.

RESULTS

The average age, height, and weight of the patients in the two groups did not differ. Preoperative SBP, mean blood pressure, diastolic blood pressure and heart rate in the high SBP group were significantly higher than those in the normal SBP group. Plasma norepinephrine concentrations in the high SBP group were significantly greater than those in the normal SBP group before and 1 h after the induction of anesthesia. Tympanic membrane temperatures in the normal SBP group started to decline further just after the induction of anesthesia, more so than that in the high SBP group. The vasoconstriction threshold in the normal SBP group was significantly lower than that in the high SBP group.

CONCLUSION

These results suggest that the higher levels of preoperative catecholamine secretion contributed to the lesser degree of intraoperative hypothermia observed in the high SBP group.

Spinal cord injury in a child caused by an accidental dural puncture with a single-shot thoracic epidural needle

IMPLICATIONS

A child experienced a spinal cord injury by an accidental dural puncture during thoracic epidural anesthesia. A magnetic resonance image was used for diagnosis and treatment.

Effect of preoperative amino acid infusion on thermoregulatory response during spinal anaesthesia

BACKGROUND

Intravenous amino acid infusion during general anaesthesia prevents decreases in core temperature resulting from increased energy expenditure and heat accumulation.

METHODS

We investigated whether such stimulation also occurs during spinal anaesthesia, which blocks sympathetic nervous activity. We examined the effect of i.v. amino acid infusion on changes in core temperature during spinal anaesthesia. Thirty-five patients were divided into two groups: an i.v. amino acid infusion group (4 kJ kg(-1) h(-1) starting 2 h before surgery); and a saline infusion group. Tympanic membrane core temperature, forearm-fingertip temperature gradient (an index of peripheral vasoconstriction) and mean skin temperature were measured for 90 min after the onset of spinal anaesthesia.

RESULTS

Changes in mean arterial pressure and heart rate did not differ significantly between the groups during the study period. Mean final core temperature 90 min after induction of spinal anaesthesia was 35.8 (SEM 0.1) degrees C in the saline group and 36.6 (0.1) degrees C in the amino acid group (P<0.05). The increased level of oxygen consumption in the amino acid group compared with the saline group was preserved even after the onset of spinal anaesthesia. The thermal vasoconstriction threshold, defined as the tympanic membrane temperature that triggered a rapid increase in forearm-fingertip temperature gradient, was increased in the amino acid group [36.8 (0.1) degrees C] compared with the saline group [36.5 (0.1) degrees C] (P<0.05).

CONCLUSIONS

Preoperative infusion of amino acids effectively prevents spinal anaesthesia-induced hypothermia by maintaining a higher metabolic rate and increasing the threshold core temperature for thermal vasoconstriction.