We analyzed the relationships among parameters of left ventricular (LV) early diastolic filling flow (EDF) obtained with pulsed Doppler echocardiography, mean pulmonary wedge pressure (PCWP) and the time constant of LV pressure fall calculated by either Weiss' (Tw) or Thompson's (Tb) method. PCWP correlated with the peak velocity (R) (r = 0.537, p less than 0.05), acceleration (Ac) (r = 0.545, p less than 0.05) and deceleration (Dc) (r = 0.606, p less than 0.01) of LVEDF. In contrast, Tb correlated only with the time to the peak of LVEDF (TPF) (r = 0.487, p less than 0.05), and Tw did not correlate with the Doppler-derived indices significantly. After correcting for the effect of PCWP, significant partial correlations between R and Tw (r = -0.535, p less than 0.05), and between Ac and both Tw (r = -0.606, p less than 0.01) and Tb (r = -0.569, p less than 0.05) were found. Dc did not correlate with Tw or Tb. These results suggest that the level of left atrial pressure may mask the relationship between parameters of LVEDF and LV relaxation, and that the relations among these variables vary with individual indices of LVEDF.
The purpose of the present study was to evaluate the feasibility of partitioning myocardial O2 consumption (VO2) into mechanical and nonmechanical components in the whole heart preparation using a negative inotrope, 2,3-butanedione monoxime (BDM), which has been reported to have a selective effect on the contractile proteins in a low concentration range (< 6 mM). In six isolated bovine red blood cell-perfused rabbit hearts, VO2 and force-time integral (FTI) were measured during infusion of varying concentrations of BDM at a constant left ventricular volume chosen such that control left ventricular peak isovolumic pressure was approximately 100 mmHg. The VO2-FTI relation with BDM concentrations < or = 5 mM was highly linear (median r = 0.98). Its VO2-axis intercept at zero FTI had a positive value (mean 23% of control, 0.014 ml O2.beat-1 x 100 g-1). To confirm the selective effect of BDM on the contractile proteins, the intracellular free Ca2+ transient was measured with the fluorescent indicator indo 1 in three isolated buffer-perfused rabbit hearts. The amplitude of the Ca2+ transient was not altered by BDM at concentrations < or = 10 mM, although left ventricular developed pressure was markedly depressed. This finding indicates that BDM < or = 10 mM does not affect excitation-contraction coupling. We conclude that the VO2-axis intercept value of the VO2-FTI relation during BDM infusion in a low concentration range represents VO2 for nonmechanical energy utilization. The BDM method to partition VO2 into mechanical and nonmechanical components is thus feasible in the whole rabbit heart.
Narcolepsy is characterized by chronic sleepiness and cataplexy, episodes of profound muscle weakness that are often triggered by strong, positive emotions. Narcolepsy with cataplexy is caused by a loss of orexin (also known as hypocretin) signaling, but almost nothing is known about the neural mechanisms through which positive emotions trigger cataplexy. Using orexin knock-out mice as a model of narcolepsy, we found that palatable foods, especially chocolate, markedly increased cataplexy and activated neurons in the medial prefrontal cortex (mPFC). Reversible suppression of mPFC activity using an engineered chloride channel substantially reduced cataplexy induced by chocolate but did not affect spontaneous cataplexy. In addition, neurons in the mPFC innervated parts of the amygdala and lateral hypothalamus that contain neurons active during cataplexy and that innervate brainstem regions known to regulate motor tone. These observations indicate that the mPFC is a critical site through which positive emotions trigger cataplexy.
Background: Since few studies of (penta)gastrin-induced histamine release from the gastric mucosa into blood has been performed, an effect of pentagastrin on histamine level of rat blood was examined by using the in vivo microdialysis method. Methods: Pentagastrin was perfused through the microdialysis probe implanted into the jugular vein of urethane-anesthetized rats or in urethane-anesthetized, totally gastrectomized rats, and dialysis samples of blood were concurrently collected. Histidine decarboxylase (HDC) activities and histamine contents in the glandular stomach and gastric acid output after pentagastrin stimulation were also investigated. Results: Pentagastrin induced a transient increase of blood histamine in a dose-dependent manner but failed to cause any increase of blood histamine in the totally gastrectomized rat. Pentagastrin also induced increases of the HDC activity in the glandular stomach and of the gastric acid output. The peak histamine level in blood occurred 40 min after pentagastrin perfusion, whereas the peak acid secretion occurred after 80–120 min and then leveled off. Conclusions: The transient increase of blood histamine induced by pentagastrin is attributable to the histamine released from enterochromaffin-like cells and could be monitored by using the in vivo microdialysis method.
To assess the clinical features of the dopamine (DA) metabolism in chronic renal failure patients (CRF), measurements were made of the plasma DA, norepinephrine (NE), epinephrine (EN) and their urinary metabolites in 6 healthy controls and 13 CRF patients before and after administration of oral DA (KW-3160, Kyowa Hakko Kogyo Co., Ltd.). The data obtained, including that for impaired DA metabolites in the patients with chronic renal failure, can be summarized as follows: I) Synthesis: In the plasma, the DA, NE and EN levels were not significantly different in the CRF patients as compared to those in normal controls, but the excretions of urinary free DA, NE and EN were markedly lower, and the free and conjugated DA, NE and EN levels were significantly decreased in the CRF patients after DA administration. These findings indicate that the plasma dopamine beta-hydroxylase activity is inhibited in CRF patients. II) Degradation: Increased levels of urinary free and conjugated 3,4-dihydroxy phenylacetic acid (DOPAC) and decreased levels of urinary conjugated homovanillic acid (HVA) were observed, indicating that the monoamine oxidase (MAO) activity in the plasma is possibly augmented, and the catecholamine O-methyl transferase (COMT) activity inhibited, in uremic patients. III) Excretion: The urinary excretions of free DOPAC, HVA, NE and vanillylmandelic acid (VMA) and of conjugated DA and DOPAC were significantly correlated with the creatinine clearance. These data suggest that the excretion of urinary DA and part of its metabolites may be regulated by the renal function.
The length of hospital stay (LOS) has become a valuable outcome measure of any operation, and it also directly impacts hospital cost.
Objectives
To identify risk factors for LOS after total knee arthroplasty (TKA) in rheumatoid arthritis (RA) and osteoarthritis (OA) patients.
Methods
We evaluated 259 (RA, 29; OA, 230) patients undergoing TKA at our hospital from July 2012 to August 2014. The RA patients group had a mean age of 70 years and included 22 females and 7 males. The OA patients group included 188 females and 42 males with a mean age of 75 years. Data collected included LOS, gender, age, body mass index (BMI), use of anti-platelet agents, operative time, use of cement for TKA, postoperative estimated blood loss and postoperative deep vein thrombosis (DVT). The diagnosis of DVT was based on ultrasonography. Multiple linear regression analysis was performed to identify variables predictive of prolonged LOS. LOS and operative time of RA and OA patients were compared using the Mann–Whitney U-test.
Results
The results of the multiple linear regression analysis indicated that age (P<0.001) and operative time (P=0.003) were risk factors for prolonged LOS. A sub-analysis of operative time revealed that male gender (P<0.001), BMI (P=0.046) and the use of cement for TKA (P=0.009) were associated with longer operative time. Of the patients undergoing TKA, the median LOS was 26 (RA, 26; OA, 26) days and the median operative time was 73 (RA, 72; OA, 74) minutes. There were no statistically significant differences between RA and OA patients.
Conclusions
We identified that elderly patients and longer operative time are associated with increased LOS among RA and OA patients undergoing TKA, and male gender, higher BMI and the use of cement for TKA are risk factors for longer operative time. There is a need to increase knowledge on the risk factors of longer LOS to reduce total hospital costs.
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